Neuroactive 19-alkoxy-17-substituted steroids, prodrugs thereof, and methods of treatment using same

ABSTRACT

The present disclosure is generally directed to neuroactive 19-alkoxy-17-substituted steroids as referenced herein, and pharmaceutically acceptable salts thereof, for use as, for example, an anesthetic, and/or in the treatment of disorders relating to GABA function and activity. The present disclosure is further directed to pharmaceutical compositions comprising such compounds.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority benefit of U.S. Provisional Patent Application Ser. No. 61/738,822, filed on Dec. 18, 2012, the entire content of which is incorporated herein by reference.

GOVERNMENT SUPPORT

The claimed subject matter was developed with Government support under NIH Grant #GM47969, awarded by the National Institute of Health. Accordingly, the Government has certain rights in the claimed subject matter.

BACKGROUND OF THE DISCLOSURE

The present disclosure is generally directed to novel compounds having utility as an anesthetic and/or in the treatment of disorders relating to GABA function and activity. More specifically, the present disclosure is directed to steroids having a 19-alkoxy-17-substituted tetracyclic structure that are neuroactive and suitable for use as an anesthetic, as well as pharmaceutically acceptable salts and prodrugs thereof, and pharmaceutical compositions containing them.

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter of the central nervous system. GABA activates two types of receptors, the inotropic GABA_(A) and the metabotropic GABA_(B) receptor. Activation of the GABA_(B) receptor by GABA causes hyperpolarization and a resultant inhibition of neurotransmitter release. The GABA_(A) receptor subtype regulates neuronal excitability and rapid mood changes, such as anxiety, panic, and stress response. GABA_(A) receptors are chloride ion channels; as a result, activation of the receptor induces increased inward chloride ion flux, resulting in membrane hyperpolarization and neuronal inhibition. Drugs that stimulate GABA_(A) receptors, such as benzodiazepines and barbiturates, have anticonvulsive effects (by reducing neuronal excitability and raising the seizure threshold), as well as anxiolytic and anesthetic effects.

The effect of certain steroids on GABA_(A) receptors has been well-established. As a result, researchers continue to pursue the discovery and synthesis of neuroactive steroids that may act as anesthetics and/or that may serve to provide treatment for disorders related to GABA function. For example, it is now widely accepted that the intravenous anesthetic alphaxalone (Compound A, below) causes general anesthesia in humans because it allosterically increases chloride currents mediated by GABA acting at GABA_(A) receptors in the brain. However, the various structural features that enable this compound to function in the way it does have, to-date, not been fully understood. For example, in contrast to alphaxalone, Δ¹⁶-alphaxalone (Compound B, below), has been observed to have greatly diminished allosteric activity at GABA_(A) receptors and is not used as an intravenous general anesthetic in humans.

The difference in performance of these two compounds, which some have attributed to the presence of the carbon-carbon double bond in the D-ring, has attracted the attention of many researchers. In fact, recently, it was determined that the effect this double bond has on anesthetic activity may depend on the group attached at C-17 on the D-ring. (See Bandyopadhyaya, A. K., et al., “Neurosteroid analogues. 15. A comparative study of the anesthetic and GABAergic actions of alphaxalone, Δ¹⁶-alphaxalone and their corresponding 17-carbonitrile analogues. Bioorg. Med. Chem. Lett., 20: 6680-4 (2010).)

In addition to anesthetic properties, neuroactive steroids may be used to treat disorders related to GABA function. For example, neuroactive steroids, such as progesterone, may be used as sedative-hypnotics, exhibiting benzodiazepine-like actions, inducing reduced sleep latency and increased non-REM sleep with only small changes in slow wave and REM sleep. Further, drugs that enhance GABA responses are often used to treat anxiety in humans. Thus, it might be expected that GABA-potentiating steroids would exhibit anxiolytic effects. Neuroactive steroids may also be used to treat depression, given that accumulating evidence suggests that patients with major depression have decreased levels of GABAergic neurosteroids and that certain treatments for depression alter levels of these steroids. Although GABA is not typically thought to play a critical role in the biology of depression, there is evidence that low GABAergic activity may predispose one to mood disorders. Finally, inhibition of NMDA receptors and enhancement of GABA_(A) receptors appear to play important roles in mediating the acute effects of ethanol in the nervous system, while related studies suggest that GABAergic neurosteroids may be involved in some of the pharmacological effects of ethanol and that neuroactive steroids may be useful in treating ethanol withdrawal.

In view of the foregoing, it is clear that there are a number of potentially advantageous uses for neurosteroids. As a result, there is a continuing need for the further synthesis and understanding of new neuroactive steroids, particularly those having utility as an anesthetic and/or in the treatment of a disorder relating to GABA function and activity.

SUMMARY OF THE DISCLOSURE

In one aspect, the present disclosure is directed to a compound having a structure of Formula (I):

or a pharmaceutically acceptable salt thereof;

wherein:

R₁ is selected from (C₁-C₄ alkyl)-O, spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O), and HO(C₁-C₄ alkyl)C(O), with R₁ preferably being in the beta position when other than ═O, and/or in one or more preferred embodiments C₁-C₄ alkyl being methyl, R₁ therefore being is selected from methoxy, spirooxirane, cyano, ═O, nitro, CH₃C(O)— and OHCH₂C(O)—;

R₂ is ═O, H, or OR_(a), where R_(a) is selected from H, optionally substituted C₁-C₄ alkyl, or optionally substituted aryl, with the proviso that when R₂ is ═O, R₈ is not present;

R₃ is H, optionally substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, optionally substituted C₂-C₄ alkynyl, or optionally substituted aryl;

R₄ is independently selected from H and unsubstituted C₁-C₄ alkyl;

R₅ is substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, or optionally substituted C₂-C₄ alkynyl (and in particular is alkoxy-substituted methyl, or even more particular is —CH₂—OR_(b), where R_(b) is C₁-C₄ alkyl, or even still more particularly is —CH₂—OCH₃);

R₆ is H, optionally substituted C₁-C₄ alkyl, or optionally substituted C₁-C₄ alkoxy;

R₇ is H, optionally substituted C₁-C₄ alkoxy, or an optionally substituted morpholinyl ring;

R₈, when present, is H or optionally substituted C₁-C₄ alkyl;

- - - denotes an optional, additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆, with the proviso that when present, the R₅—H substituent is not present; and,

- - - denotes an optional, additional C—C bond, resulting in a C═C bond between C₁₆-C₁₇, with the proviso that when present, the R₁ is not ═O.

The present disclosure is further directed to a pharmaceutically acceptable salt of the noted compounds, or alternatively to prodrugs thereof. In one particular embodiment, the present disclosure is directed to a compound having a structure of Formula (II):

or a pharmaceutically acceptable salt thereof;

wherein:

R₁ is selected from (C₁-C₄ alkyl)-O, spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O), and HO(C₁-C₄ alkyl)C(O), with R₁ preferably being in the beta position when other than ═O, and/or in one or more preferred embodiments C₁-C₄ alkyl being methyl, R₁ therefore being is selected from methoxy, spirooxirane, cyano, ═O, nitro, CH₃C(O)— and OHCH₂C(O)—;

R₂ is ═O, H, or OR_(a), where R_(a) is selected from H, optionally substituted C₁-C₄ alkyl, or optionally substituted aryl, with the proviso that when R₂ is ═O, R₈ is not present;

R_(x) is ═O or OR_(d), where R_(d) is H or C(O)R_(e), where R_(e) is optionally substituted C₁-C₂₂ alkyl or optionally substituted C₂-C₂₂ alkenyl, with the proviso that when R_(x) is OH, it is in the beta configuration;

R₄ is independently selected from H and unsubstituted C₁-C₄ alkyl;

R₅ is substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, or optionally substituted C₂-C₄ alkynyl (and in particular is alkoxy-substituted methyl, or even more particular is —CH₂—OR_(b), where R_(b) is C₁-C₄ alkyl, or even still more particularly is —CH₂—OCH₃);

R₆ is H, optionally substituted C₁-C₄ alkyl, or optionally substituted C₁-C₄ alkoxy;

R₇ is H, optionally substituted C₁-C₄ alkoxy, or an optionally substituted morpholinyl ring;

R₈, when present, is H or optionally substituted C₁-C₄ alkyl;

- - - denotes an optional, additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆, with the proviso that when present, the C₅—H substituent is not present; and,

- - - denotes an optional, additional C—C bond, resulting in a C═C bond between C₁₆-C₁₇, with the proviso that when present, the R₁ is not ═O,

provided that the compound does not have one of the following structures:

or alternatively provided that: (i) when R_(x) is ═O, a C═C bond is present between C₄-C₅, and R₅ is CH₂OCH₃, then R₁ is selected from methoxy, spirooxirane, cyano, nitro, and CH₃C(O)—; and/or (ii) when R_(x) is beta-OH, a C═C bond is present between C₅-C₆, and R₅ is CH₂OCH₃, then R₁ is selected from methoxy, spirooxirane, cyano, nitro, and HOCH₂C(O)—.

The present disclosure is still further directed to a pharmaceutical composition comprising a therapeutically effective amount of one or more of the above-noted steroids, or prodrugs, or pharmaceutically acceptable salts thereof, and optionally a pharmaceutically acceptable carrier. The present disclosure also provides kits comprising steroids, salts thereof, pro-drugs thereof, and/or pharmaceutical compositions thereof.

The present disclosure further provides methods of inducing anesthesia in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of one or more of the above-noted steroids, or prodrugs, or pharmaceutically acceptable salts thereof, or a pharmaceutical composition thereof.

The present disclosure further provides methods of treating disorders related to GABA function in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of one or more of the above-noted steroids, or prodrugs, or pharmaceutically acceptable salts thereof, or a pharmaceutical composition thereof. In certain embodiments, the disorder is selected from the group consisting of insomnia, mood disorders, convulsive disorders, anxiety, or symptoms of ethanol withdrawal.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

In accordance with the present disclosure, it has been discovered that compounds having certain 17-substituted steroid structures, more specifically certain 19-alkoxy-17-substituted steroid structures, and even more specifically certain 19-methoxy-17-substituted steroid structures, are neuroactive and are also suitable for use as anesthetics and in the treatment of disorders associated with GABA function, as well as pharmaceutically acceptable salts and prodrugs thereof. The compounds may be used, for example, as an effective continuous infusion sedative for non-surgical procedures (e.g., colonoscopy). The compounds also offer advantages over anesthetics known in the art, such as a lower likelihood for bacterial contamination, as well as an improved relationship with solubilizing agents.

1. Steroid Structure

Generally speaking, the steroid of the present disclosure has a tetracyclic, fused ring structure, such as a cyclopenta[a]phenanthrene ring system (an embodiment of which is illustrated and discussed in greater detail below), wherein the C₃-position of the A ring has a hydroxyl substituent in the α-position, and the C₁₇-position of the D ring has a substituent attached thereto selected from the group consisting of methoxy, spirooxirane, cyano, ═O, nitro, CH₃C(O)—, and HOCH₂C(O)— (with R₁ preferably being in the beta position when other than ═O).

More particularly, however, the present disclosure is directed, in certain embodiments, to a steroid having the structure of Formula (I):

or a pharmaceutically acceptable salt thereof;

wherein:

R₁ is selected from (C₁-C₄ alkyl)-O (e.g., methoxy, ethoxy, propoxy, butoxy), spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O) (e.g., CH₃C(O), CH₃CH₂C(O), CH₃CH₂ CH₂C(O), CH₃CH₂ CH₂ CH₂C(O)), and HO(C₁-C₄ alkyl)C(O) (e.g., HOCH₂C(O), HOCH₂CH₂C(O), HOCH₂CH₂ CH₂C(O), HOCH₂CH₂ CH₂ CH₂C(O)), with R₁ preferably being in the beta position when other than ═O, and/or in one or more preferred embodiments C₁-C₄ alkyl being methyl, R₁ therefore being is selected from methoxy, spirooxirane, cyano, ═O, nitro, CH₃C(O)— and OHCH₂C(O)—;

R₂ is ═O, H, or OR_(a), where R_(a) is selected from H, optionally substituted C₁-C₄ alkyl, or optionally substituted aryl, with the proviso that when R₂ is ═O, R₈ is not present;

R₃ is H, optionally substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, optionally substituted C₂-C₄ alkynyl, or optionally substituted aryl;

R₄ is independently selected from H and unsubstituted C₁-C₄ alkyl;

R₅ is substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, or optionally substituted C₂-C₄ alkynyl (and in particular is alkoxy-substituted methyl, or even more particular is —CH₂—OR_(b), where R_(b) is C₁-C₄ alkyl, or even still more particularly is —CH₂—OCH₃);

R₆ is H, optionally substituted C₁-C₄ alkyl, or optionally substituted C₁-C₄ alkoxy;

R₇ is H, optionally substituted C₁-C₄ alkoxy, or an optionally substituted morpholinyl ring;

R₈, when present, is H or optionally substituted C₁-C₄ alkyl;

- - - denotes an optional, additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆, with the proviso that when present, the R₅—H substituent is not present; and,

- - - denotes an optional, additional C—C bond, resulting in a C═C bond between C₁₆-C₁₇, with the proviso that when present, the R₁ is not ═O.

As generally defined above, R₁ is selected from (C₁-C₄ alkyl)-O, spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O), and HO(C₁-C₄ alkyl)C(O). In certain embodiments, R₁ is preferably in the beta position (when other than ═O, or when a C═C is not present between C₁₆-C₁₇. In certain embodiments, R₁ is selected from (C₁-C₄ alkyl)-O (e.g., methoxy, ethoxy, propoxy, butoxy), spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O) (e.g., CH₃C(O), CH₃CH₂C(O), CH₃CH₂ CH₂C(O), CH₃CH₂ CH₂ CH₂C(O)), and HO(C₁-C₄ alkyl)C(O) (e.g., HOCH₂C(O), HOCH₂CH₂C(O), HOCH₂CH₂ CH₂C(O), HOCH₂CH₂ CH₂ CH₂C(O)). In certain embodiments, C₁-C₄ alkyl is methyl, R₁ therefore being is selected from methoxy, spirooxirane, cyano, ═O, nitro, CH₃C(O)— and OHCH₂C(O)—.

As generally defined above, R₂ is ═O, H, or OR_(a), where R_(a) is selected from H, optionally substituted C₁-C₄ alkyl, or optionally substituted aryl, with the proviso that when R₂ is ═O, R₈ is not present. In certain embodiments, R₂ is ═O and R₈ is not present. In certain embodiments, R₂ is H. In certain embodiments, R₂ is OR_(a). In certain embodiments, R₂ is OR_(a) and R_(a) is optionally substituted C₁, C₂, C₃, or C₄ alkyl (e.g., methyl, ethyl), optionally substituted benzyl, or C₁, C₂, C₃, or C₄ alkyl substituted with O-aryl, such as O-benzyl. In certain embodiments, R₂ is OR_(a) and R_(a) is optionally substituted aryl. In certain embodiments, R₂ is OR_(a) and R_(a) is H.

As generally defined above, R₃ is H, optionally substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, optionally substituted C₂-C₄ alkynyl, or optionally substituted aryl. In certain embodiments, R₃ is H. In certain embodiments, R₃ is optionally substituted C₁, C₂, C₃ or C₄ alkyl (e.g., methyl, ethyl, trifluoromethyl, difluoromethyl). In certain embodiments, R₃ is methyl. In certain embodiments, R₃ is trifluoromethyl. In certain embodiments, R₃ is optionally substituted C₂, C₃ or C₄ alkenyl (e.g., optionally substituted allyl). In certain embodiments, R₃ is optionally substituted C₂, C₃, or C₄ alkynyl (e.g., optionally substituted acetylene or optionally substituted propargyl). In certain embodiments, R₃ is optionally substituted aryl (e.g., optionally substituted phenyl, such as phenyl substituted with OH, methyl, or COR_(c), where R_(c) is optionally substituted C₁-C₂₂ alkyl or optionally substituted C₂-C₂₂ alkenyl, including for example optionally substituted C₁, C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇, C₁₈, C₁₉, C₂₀, C₂₁, or C₂₂ alkyl or C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇, C₁₈, C₁₉, C₂₀, C₂₁, or C₂₂ alkenyl).

As generally defined above, R₄ is H or unsubstituted C₁-C₄ alkyl. In certain embodiments, R₄ is H. In certain embodiments, R₄ is unsubstituted C₁, C₂, C₃ or C₄ alkyl (e.g., methyl, ethyl, n-propyl, isopropyl, or n-butyl).

As generally defined above, R₅ is substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, or optionally substituted C₂-C₄ alkynyl. In certain embodiments, R₅ is substituted C₁-C₄ alkyl, and in particular is alkoxy-substituted C₁-C₄ alkyl. In other particular embodiments, R₅ is substituted methyl, and more particularly is alkoxy-substituted methyl (or even more particularly is —CH₂—OR_(b), where R_(b) is C₁-C₄ alkyl, or even still more particularly is —CH₂—OCH₃). In other embodiments, R₅ is optionally substituted C₂-C₄ alkenyl. In other embodiments, R₅ is optionally substituted C₂-C₄ alkynyl.

As generally defined above, R₆ is H, optionally substituted C₁-C₄ alkyl, or optionally substituted C₁-C₄ alkoxy. In certain embodiments, R₆ is H. In certain embodiments, R₆ is optionally substituted C₁, C₂, C₃, or C₄ alkyl (e.g., methyl). In certain embodiments, R₆ is optionally substituted C₁, C₂, C₃ or C₄ alkoxy (e.g., methoxy, ethoxy, n-propyloxy, isopropyloxy, or n-butoxy). In certain embodiments, when R₆ is a non-hydrogen group, R₆ is in the alpha (down) position. In certain preferred embodiments, however, when R₆ is a non-hydrogen group, R₆ is in the beta (up) position.

As generally defined above, R₇ is H, optionally substituted C₁-C₄ alkoxy, or an optionally substituted morpholinyl ring. In certain embodiments, R₇ is H. In certain embodiments, R₇ is optionally substituted C₁, C₂, C₃ or C₄ alkoxy (e.g., methoxy, ethoxy, n-propyloxy, isopropyloxy, or n-butoxy). In certain embodiments, R₇ is an optionally substituted morpholinyl ring. In certain embodiments, when R₇ is a non-hydrogen group, R₇ is in the alpha (down) position. In certain preferred embodiments, however, when R₇ is a non-hydrogen group, R₇ is in the beta (up) position.

As generally defined above, R₈, when present, is H or optionally substituted C₁-C₄ alkyl. In certain embodiments, R₈ is H. In certain embodiments, R₈ is C₁, C₂, C₃ or C₄ optionally substituted alkyl (e.g., methyl). In certain embodiments, when R₈ is optionally substituted C₁-C₄ alkyl, R₈ is in the alpha (down) position. In certain embodiments, when R₈ is optionally substituted C₁-C₄ alkyl, R₈ is in the beta (up) position.

In certain embodiments, R₂ and R₈ are both H. In certain embodiments, R₂ is OR_(a) and R₈ is H.

As generally defined above, - - - denotes an optional, additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆, with the proviso that when present, the C₅—H substituent is not present. In certain embodiments, the additional C—C bond is absent, and the hydrogen at C₅ is in the alpha or beta position. In certain embodiments, the additional C—C bond is absent, and the hydrogen at C₅ is in the alpha (down) position. In certain embodiments, the additional C—C bond is absent, and the hydrogen at C₅ is in the beta (up) position. In certain embodiments, - - - denotes an additional C—C bond, resulting in a C═C bond between C₄-C₅. In certain embodiments, - - - denotes an additional C—C bond, resulting in a C═C bond between C₅-C₆.

As generally defined above, - - - denotes an optional, additional C—C bond, resulting in a C═C bond, between C₁₆-C₁₇, with the proviso that when present, the R₁ is other than ═O. In certain embodiments, the additional C—C bond is absent (i.e., there is not C═C bond), and therefore R₁ may be in the alpha or beta position. In certain embodiments, the additional C—C bond is absent, and the R₁ is in the alpha (down) position. In certain embodiments, the additional C—C bond is absent, and the R₁ is in the beta (up) position.

It is to be noted that the present disclosure contemplates and is intended to encompass all of the various combinations and permutations (i.e., combinations of substituent options, locations and stereochemical configurations) possible here.

For example, in various embodiments, compounds of the present disclosure may be selected from among those encompassed by the structure of Formula (I), wherein R₂ is ═O; alternatively, R₂ may be H and R₈ is H (e.g., C₁₁ thus having two hydrogen atoms bound thereto as substituents). In certain embodiments, R₂ may be OR_(a), wherein R_(a) is methyl, optionally substituted benzyl, or C₁-C₄ alkyl substituted with O-aryl, such as O-benzyl. In certain embodiments, R₃ may be H, methyl, trifluoromethyl, or substituted aryl (e.g., substituted phenyl, which in turn may be optionally substituted such as, for example, with OH, methyl, or COR_(c), where R_(c)═C₁-C₄ alkyl); further, when R₃ is something other than H, R₃ is preferably in the β-position. In certain embodiments, each of R₄ and R₆ are independently selected from H and methyl, R₅ being in the β-configuration and R₆ optionally being in the α-configuration or β-configuration (e.g., when R₆ is methyl), which the β-configuration being preferred. In certain embodiments, R₇ is selected from H, methoxy, ethoxy, and an optionally substituted morpholinyl ring; further, when R₇ is something other than H, R₇ is preferably in the β-position. In certain embodiments, R₈, when present, is selected from H or optionally substituted C₁-C₄ alkyl. In certain embodiments, R₈ is methyl (e.g., methyl in the alpha-configuration).

In certain embodiments, the C₅—H is in the alpha configuration and the R₅ is, for example, a substituted methyl group (e.g., alkoxy-substituted methyl, or in particular a methoxy-substituted methyl) in the beta configuration. In certain embodiments, the C5-H is in the beta configuration and R₅ is, for example, a substituted methyl (e.g., a methoxy-substituted methyl) group in the beta configuration. In certain embodiments, R₆ is H. In certain embodiments, R₄ is methyl. In certain embodiments, R₂ is ═O or methoxy.

Accordingly, as noted, the steroid of Formula (I) may encompass a number of various structures in accordance with the present disclosure.

In certain embodiments, wherein R₁ is as defined above, R₃ is in the beta position, R₄ is methyl, R₅ is substituted methyl in the beta position, and R₆ is H, provided is a compound of Formula (I-a):

or a pharmaceutically acceptable salt thereof, wherein - - -, R₂, R₃, R₇ and R₈ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein R₂ is ═O and R₈ is absent, provided is a compound of Formula (I-b):

or a pharmaceutically acceptable salt thereof, wherein - - -, R₃ and R₇ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein R₂ and R₈ are H, provided is a compound of Formula (I-c):

or a pharmaceutically acceptable salt thereof, wherein - - -, R₂, R₃, and R₇ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein R₂ is OR_(a) and R₈ is H, provided is a compound of Formula (I-d):

or a pharmaceutically acceptable salt thereof, wherein - - -, R₃, R₂, and R_(a) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein R₇ is H, provided is a compound of Formula (I-e):

or a pharmaceutically acceptable salt thereof, wherein - - -, R₂, R₃, and R₈ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein each instance of - - - is absent and C₅—H is in the alpha position, provided is a compound of Formula (I-f):

or a pharmaceutically acceptable salt thereof, wherein R₂, R₃, R₇ and R₈ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein R₇ is H, provided is a compound of Formula (I-g):

or a pharmaceutically acceptable salt thereof, wherein R₂, R₃, and R₈ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein R₂ is ═O, provided is a compound of Formula (I-h):

or a pharmaceutically acceptable salt thereof, wherein R₃ and R₂ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein R₂ is OR_(a), provided is a compound of Formula (I-i):

or a pharmaceutically acceptable salt thereof, wherein R_(a), R₃, and R₇ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein - - - represents an additional C—C bond, resulting in a C═C bond between C₄-C₅ provided is a compound of Formula (I-j):

or a pharmaceutically acceptable salt thereof, wherein R₃, R₂, R₇ and R₈ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

In certain embodiments of Formula (I), wherein - - - represents an additional C—C bond, resulting in a C═C bond between C₅-C₆ provided is a compound of Formula (I-k):

or a pharmaceutically acceptable salt thereof, wherein R₃, R₂, R₇ and R₈ are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position.

It is to be noted that, in one or more of the preferred embodiments detailed above, R₁ may, in particular, be selected from methoxy (or more generally lower alkoxy, e.g., —O—(C₁-C₄)), or alternatively selected from CH₃C(O)— or HOCH₂C(O)— (or more generally substituted or unsubstituted lower alkyl-carbonyl, e.g., (C₁-C₄)C(O)—, wherein one or more of the carbon atoms is optionally substituted, such as for example by a hydroxyl group). Alternatively, R₁ may be selected from nitro or cyano, with an optional C═C being present between C₁₆-C₁₇. In yet another alternative embodiment, C₁₇ may be a carbonyl carbon (i.e., R₁ is ═O), or it may be part of an oxirane ring fused with the D-ring (i.e., R₁ being a spirooxirane substituent, wherein C₁₇ is the carbon atom common to both rings).

Exemplary compounds of Formula (I) include, but are not limited to, the following:

and pharmaceutically acceptable salts thereof, wherein in one preferred embodiment R_(b) is CH₃.

In certain embodiments, the steroid of Formula (I) is selected from the group consisting of:

and pharmaceutically acceptable salts thereof, wherein R₃ is as defined above, and in one particular embodiment is H, and further wherein in this or another preferred embodiment R_(b) is CH₃.

In certain embodiments, the steroid of Formula (I) is selected from the group consisting of:

and pharmaceutically acceptable salts thereof, wherein R₃ is as defined above, and in one particular embodiment is H, and further wherein in this or another preferred embodiment R_(b) is CH₃.

In certain embodiments, the steroid of Formula (I) is selected from the group consisting of:

and a pharmaceutically acceptable salt thereof, wherein R₃ and/or R₁ are as defined above, and in one particular embodiment R₃ is H and R₁ is methoxy, and further wherein in these or other preferred embodiments R_(b) is CH₃.

In certain embodiments, the steroid of Formula (I) is selected from the group consisting of:

and a pharmaceutically acceptable salt thereof, wherein R₃ is as defined above, and in one particular embodiment is H, and further wherein in this or another preferred embodiment R_(b) is CH₃.

In certain embodiments, the steroid of Formula (I) is selected from the group consisting of:

and a pharmaceutically acceptable salt thereof, wherein R₃ is as defined above, and in one particular embodiment is H, and further wherein in this or another preferred embodiment R_(b) is CH₃.

In this regard it is to be noted that the structures provided above are of various exemplary embodiments. As such, they should not be viewed in a limiting sense.

2. Prodrug Structure

In another particular embodiment, the present disclosure is in general directed to prodrugs of the various steroids detailed above. Generally speaking, as used herein, a “prodrug” refers to an inactive, or significantly less active, form of the steroids detailed above (and in particular the steroids of Formula (I)), which after administration is metabolized in vivo into one or more active metabolites of the steroid of Formula (I). The prodrug may be formed using means generally known in the art, and therefore may take essentially any form that would be recognized to one of ordinary skill in the art. The prodrugs of the present disclosure may advantageously provide improved absorption, distribution, metabolism and/or excretion optimization, as well as improved oral bioavailability of the steroids detailed above (and in particular the steroids of Formula (I)).

In another particular embodiment of the present disclosure the prodrug of a steroid disclosed herein has a structure of Formula (II):

or a pharmaceutically acceptable salt thereof;

wherein:

R₁ is selected from (C₁-C₄ alkyl)-O (e.g., methoxy, ethoxy, propoxy, butoxy), spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O) (e.g., CH₃C(O), CH₃CH₂C(O), CH₃CH₂ CH₂C(O), CH₃CH₂ CH₂ CH₂C(O)), and HO(C₁-C₄ alkyl)C(O) (e.g., HOCH₂C(O), HOCH₂CH₂C(O), HOCH₂CH₂ CH₂C(O), HOCH₂CH₂ CH₂ CH₂C(O)), with R₁ preferably being in the beta position when other than ═O, and/or in one or more preferred embodiments C₁-C₄ alkyl being methyl, R₁ therefore being is selected from methoxy, spirooxirane, cyano, ═O, nitro, CH₃C(O)— and OHCH₂C(O)—;

R₂ is ═O, H, or OR_(a), where R_(a) is selected from H, optionally substituted C₁-C₄ alkyl, or optionally substituted aryl, with the proviso that when R₂ is ═O, R₈ is not present;

R_(x) is ═O or OR_(d), where R_(d) is H or C(O)R_(e), where R_(e) is optionally substituted C₁-C₂₂ alkyl or optionally substituted C₂-C₂₂ alkenyl, with the proviso that when R_(x) is OH, it is in the beta configuration;

R₄ is independently selected from H and unsubstituted C₁-C₄ alkyl;

R₅ is substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, or optionally substituted C₂-C₄ alkynyl (and in particular is alkoxy-substituted methyl, or even more particular is —CH₂—OR_(b), where R_(b) is C₁-C₄ alkyl, or even still more particularly is —CH₂—OCH₃);

R₆ is H, optionally substituted C₁-C₄ alkyl, or optionally substituted C₁-C₄ alkoxy;

R₇ is H, optionally substituted C₁-C₄ alkoxy, or an optionally substituted morpholinyl ring;

R₈, when present, is H or optionally substituted C₁-C₄ alkyl;

- - - denotes an optional, additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆, with the proviso that when present, the C₅—H substituent is not present; and,

- - - denotes an optional, additional C—C bond, resulting in a C═C bond between C₁₆-C₁₇, with the proviso that when present, the R₁ is not ═O,

provided that the compound does not have one of the following structures:

or alternatively provided that: (i) when R_(x) is ═O, a C═C bond is present between C₄-C₅, and R₅ is CH₂OCH₃, then R₁ is selected from methoxy, spirooxirane, cyano, nitro, and CH₃C(O)—; and/or (ii) when R_(x) is beta-OH, a C═C bond is present between C₅-C₆, and R₅ is CH₂OCH₃, then R₁ is selected from methoxy, spirooxirane, cyano, nitro, and HOCH₂C(O)—.

In this regard, it is to be noted that the present disclosure contemplates and is intended to encompass all of the various combinations and permutations (i.e., combinations of substituent options, locations and stereochemical configurations) possible here.

As generally defined above, R₁ is selected from (C₁-C₄ alkyl)-O, spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O), and HO(C₁-C₄ alkyl)C(O). In certain embodiments, R₁ is preferably in the beta position (when other than ═O, or when a C═C is not present between C₁₆-C₁₇). In certain embodiments, R₁ is selected from (C₁-C₄ alkyl)-O (e.g., methoxy, ethoxy, propoxy, butoxy), spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O) (e.g., CH₃C(O), CH₃CH₂C(O), CH₃CH₂ CH₂C(O), CH₃CH₂ CH₂ CH₂C(O)), and HO(C₁-C₄ alkyl)C(O) (e.g., HOCH₂C(O), HOCH₂CH₂C(O), HOCH₂CH₂ CH₂C(O), HOCH₂CH₂ CH₂ CH₂C(O)). In certain embodiments, C₁-C₄ alkyl is methyl, R₁ therefore being is selected from methoxy, spirooxirane, cyano, ═O, nitro, CH₃C(O)— and OHCH₂C(O)—.

As generally defined above, R_(x) is ═O or OR_(d), where R_(d) is H or C(O)R_(e), where R_(e) is optionally substituted C₁-C₂₂ alkyl or optionally substituted C₂-C₂₂ alkenyl (including for example optionally substituted C₁, C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇, C₁₈, C₁₉, C₂₀, C₂₁, or C₂₂ alkyl or C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, C₁₇, C₁₈, C₁₉, C₂₀, C₂₁, or C₂₂ alkenyl), with the proviso that when R_(x) is OH, it is in the beta (up) configuration. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, R_(x) is OR_(d), R_(d) is C(O)R_(e), and R_(e) is optionally substituted C₁-C₂₂ alkyl or optionally substituted C₂-C₂₂ alkenyl, e.g., C(O)CH₃, and in such instances, the group Rx is provided in either the alpha or beta configuration (with the beta configuration being preferred). In certain embodiments, wherein R_(x) is OR_(d), and R_(d) is H, then R_(x) is OH in the beta (up) configuration.

As generally defined above, R₂ is ═O, H, or OR_(a), where R_(a) is selected from H, optionally substituted C₁-C₄ alkyl, or optionally substituted aryl, with the proviso that when R₂ is ═O, R₈ is not present. In certain embodiments, R₂ is ═O and R₈ is not present. In certain embodiments, R₂ is H. In certain embodiments, R₂ is OR_(a). In certain embodiments, R₂ is OR_(a) and R_(a) is optionally substituted C₁, C₂, C₃ or C₄ alkyl (e.g., methyl, ethyl), optionally substituted benzyl, or C₁, C₂, C₃ or C₄ alkyl substituted with O-aryl, such as O-benzyl. In certain embodiments, R₂ is OR_(a) and R_(a) is optionally substituted aryl. In certain embodiments, R₂ is OR_(a) and R_(a) is H.

As generally defined above, R₄ is H or unsubstituted C₁-C₄ alkyl. In certain embodiments, R₄ is H. In certain embodiments, R₄ is unsubstituted C₁, C₂, C₃ or C₄ alkyl (e.g., methyl, ethyl, n-propyl, isopropyl, or n-butyl).

As generally defined above, R₅ is substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, or optionally substituted C₂-C₄ alkynyl. In certain embodiments, R₅ is substituted C₁-C₄ alkyl, and in particular is alkoxy-substituted C₁-C₄ alkyl. In other particular embodiments, R₅ is substituted methyl, and more particularly is alkoxy-substituted methyl (or even more particularly is —CH₂—OR_(b), where R_(b) is C₁-C₄ alkyl, or even still more particularly is —CH₂—OCH₃). In other embodiments, R₅ is optionally substituted C₂-C₄ alkenyl. In other embodiments, R₅ is optionally substituted C₂-C₄ alkynyl.

As generally defined above, R₆ is H, optionally substituted C₁-C₄ alkyl, or optionally substituted C₁-C₄ alkoxy. In certain embodiments, R₆ is H. In certain embodiments, R₆ is optionally substituted C₁, C₂, C₃, or C₄ alkyl (e.g., methyl). In certain embodiments, R₆ is optionally substituted C₁, C₂, C₃ or C₄ alkoxy (e.g., methoxy, ethoxy, n-propyloxy, isopropyloxy, or n-butoxy). In certain embodiments, when R₆ is a non-hydrogen group, R₆ is in the alpha (down) position. In certain preferred embodiments, however, when R₆ is a non-hydrogen group, R₆ is in the beta (up) position.

As generally defined above, R₇ is H, optionally substituted C₁-C₄ alkoxy, or an optionally substituted morpholinyl ring. In certain embodiments, R₇ is H. In certain embodiments, R₇ is optionally substituted C₁, C₂, C₃ or C₄ alkoxy (e.g., methoxy, ethoxy, n-propyloxy, isopropyloxy, or n-butoxy). In certain embodiments, R₇ is an optionally substituted morpholinyl ring. In certain embodiments, when R₇ is a non-hydrogen group, R₇ is in the alpha (down) position. In certain preferred embodiments, however, when R₇ is a non-hydrogen group, R₇ is in the beta (up) position.

As generally defined above, R₈, when present, is H or optionally substituted C₁-C₄ alkyl. In certain embodiments, R₈ is H. In certain embodiments, R₈ is C₁, C₂, C₃ or C₄ optionally substituted alkyl (e.g., methyl). In certain embodiments, when R₈ is optionally substituted C₁-C₄ alkyl, R₈ is in the alpha (down) position. In certain embodiments when R₈ is optionally substituted C₁-C₄ alkyl, R₈ is in the beta (up) position.

In certain embodiments, R₂ and R₈ are both H. In certain embodiments, R₂ is OR_(a) and R₈ is H.

As generally defined above, - - - denotes an optional, additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆, with the proviso that when present, the C₅—H substituent is not present. In certain embodiments, the additional C—C bond is absent, and the hydrogen at C₅ is in the alpha or beta position. In certain embodiments, the additional C—C bond is absent, and the hydrogen at C₅ is in the alpha (down) position. In certain embodiments, the additional C—C bond is absent, and the hydrogen at C₅ is in the beta (up) position. In certain embodiments, - - - denotes an additional C—C bond, resulting in a C═C bond between C₄-C₅. In certain embodiments, - - - denotes an additional C—C bond, resulting in a C═C bond between C₅-C₆.

As generally defined above, - - - denotes an optional, additional C—C bond, resulting in a C═C bond, between C₁₆-C₁₇, with the proviso that when present, the R₁ is other than ═O. In certain embodiments, the additional C—C bond is absent (i.e., there is not C═C bond), and therefore R₁ may be in the alpha or beta position. In certain embodiments, the additional C—C bond is absent, and the R₁ is in the alpha (down) position. In certain embodiments, the additional C—C bond is absent, and the R₁ is in the beta (up) position.

In certain embodiments, prodrugs of the present disclosure may be selected from among those encompassed by the structure of Formula (II), wherein R₂ is ═O. In certain embodiments, R₂ is H and R₈ is H, e.g., C₁₁ thus having two hydrogen atoms bound thereto as substituents. In certain embodiments, R₂ may be OR_(a), wherein R_(a) is methyl, optionally substituted benzyl, or C₁-C₄ alkyl substituted with O-aryl, such as O-benzyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is 3-hydroxy. In certain embodiments, R_(x) is OR_(d), where R_(d) is H or C(O)R_(e), where R_(e) is optionally substituted C₁-C₄ alkyl (e.g., methyl). In certain embodiments, each of R₄ and R₆ are independently selected from H and methyl. In certain embodiments, R₆ is optionally substituted alkyl, e.g., methyl, optionally in the alpha-configuration when the carbon-carbon double bond between C₅-C₆ is absent. In certain embodiments, R₆ is optionally substituted alkyl, e.g., methyl, optionally in the beta-configuration when the carbon-carbon double bond between C₅-C₆ is absent. In certain embodiments, R₇ is selected from H, methoxy, ethoxy, and an optionally substituted morpholinyl ring. In certain embodiments, R₇ is a non-hydrogen group, R₇ is in the 3-position. In certain embodiments, a carbon-carbon double bond (or unsaturated bond) may be present between the C₄-C₅, or C₅-C₆, carbon atoms. In certain embodiments, R₈, when present, is selected from H or optionally substituted C₁-C₄ alkyl, preferably methyl and more preferably alpha-methyl.

In certain embodiments, R_(x) is OH and in the beta position. In certain embodiments, a carbon-carbon double bond is present between the C₄-C₅ carbon atoms. In certain embodiments, a carbon-carbon double bond is present between the C₅-C₆ carbon atoms. In certain embodiments, R₂ is ═O. In certain embodiments, R₂ is methoxy. In certain embodiments, R₇ is H. In certain embodiments, R₇ is β-methoxy. In certain embodiments, R₇ is 3-ethoxy.

In certain embodiments, wherein R₄ is methyl, R₅ is substituted methyl in the beta position, and R₆ is H, provided is a compound of Formula (II-a):

or a pharmaceutically acceptable salt thereof, wherein R₁, - - -, R_(x), R₂, R₇ (preferably in the beta configuration) and R₈ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein R₂ is ═O and R₈ is absent, provided is a compound of Formula (II-b):

or a pharmaceutically acceptable salt thereof, wherein R₁, - - -, R_(x), and R₇ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein R₂ is H and R₈ is H, provided is a compound of Formula (II-c):

or a pharmaceutically acceptable salt thereof, wherein R₁, - - -, R_(x), and R₇ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the alpha position. In certain embodiments, each instance of - - - between C₅-C₆ and C₆-C₇ is absent and C₅—H is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein R₂ is OR_(a) and R₈ is H, provided is a compound of Formula (II-d):

or a pharmaceutically acceptable salt thereof, wherein R₁, - - -, R₃, R₇ (preferably in the beta configuration), and R_(a) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, each instance of - - - is absent C₅—H is in the alpha position. In certain embodiments, each instance of - - - is absent C₅—H is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein R₇ is H, provided is a compound of Formula (II-e):

or a pharmaceutically acceptable salt thereof, wherein R₁, - - -, R_(x), R₂ and R₈ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - is absent C₅—H is in the alpha position. In certain embodiments, each instance of - - - is absent C₅—H is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in either a C═C bond between C₄-C₅ or C₅-C₆. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein each instance of - - - is absent C₅—H is in the alpha position, provided is a compound of Formula (II-f):

or a pharmaceutically acceptable salt thereof, wherein R₁, R_(x), R₂, R₇ (preferably in the beta configuration) and R₈ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein R₇ is H, provided is a compound of Formula (II-g):

or a pharmaceutically acceptable salt thereof, wherein R₁, R_(x), R₂ and R₈ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein R₂ is ═O, provided is a compound of Formula (II-h):

or a pharmaceutically acceptable salt thereof, wherein R₁, R_(x) and R₂ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein R₂ is OR_(a), provided is a compound of Formula (II-i):

or a pharmaceutically acceptable salt thereof, wherein R₁, R_(x), R_(a), and R₂ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein - - - represents an additional C—C bond, resulting in a C═C bond between C₄-C₅ provided is a compound of Formula (II-j):

or a pharmaceutically acceptable salt thereof, wherein R₁, R_(x), R₂, R₇ (preferably in the beta configuration) and R₈ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

In certain embodiments of Formula (II), wherein - - - represents an additional C—C bond, resulting in a C═C bond between C₅-C₆ provided is a compound of Formula (II-k):

or a pharmaceutically acceptable salt thereof, wherein R₁, R_(x), R₂, R₇ (preferably in the beta configuration) and R₈ (preferably in the beta configuration) are as defined herein, and further wherein R_(b) is optionally substituted C₁-C₄ alkyl. In certain embodiments, R_(x) is ═O. In certain embodiments, R_(x) is OH in the beta (up) configuration. In certain embodiments, each instance of - - - between C₁₆-C₁₇ is absent and R₁ is in the beta position. In certain embodiments, - - - represents an additional C—C bond, resulting in a C═C between C₁₆-C₁₇.

It is to be noted that, in one or more of the preferred embodiments detailed above, R₁ may, in particular, be selected from methoxy (or more generally lower alkoxy, e.g., —O—(C₁-C₄)), or alternatively selected from CH₃C(O)— or HOCH₂C(O)— (or more generally substituted or unsubstituted lower alkyl-carbonyl, e.g., (C₁-C₄)C(O)—, wherein one or more of the carbon atoms is optionally substituted, such as for example by a hydroxyl group). Alternatively, R₁ may be selected from nitro or cyano, with an optional C═C being present between C₁₆-C₁₇. In yet another alternative embodiment, C₁₇ may be a carbonyl carbon (i.e., R₁ is ═O), or it may be part of an oxirane ring fused with the D-ring (i.e., R₁ being a spirooxirane substituent, wherein C₁₇ is the carbon atom common to both rings).

Exemplary compounds of Formula (II) include, but are not limited to:

and pharmaceutically acceptable salts thereof, wherein in one preferred embodiment R_(b) is CH₃.

In this regard it is to be noted that the structures provided above are of various exemplary embodiments. As such, they should not be viewed in a limiting sense.

3. Methods of Preparation and Pharmaceutical Compositions

It is to be noted that the compounds or steroids of the present disclosure, or the prodrugs thereof, may in various embodiments be prepared or used in accordance with means generally known in the art. For example, in certain embodiments, the steroids or prodrugs of the present disclosure may be prepared or used in a pharmaceutically acceptable salt form, for example, where R₇ is an optionally substituted morpholinyl ring. Suitable salt forms include, for example, citrate or chloride salt forms.

In various embodiments of the present disclosure, a pharmaceutical composition is disclosed that may comprise a steroid, a prodrug, or a combination of two or more thereof in accordance with the formulas of the present disclosure. The compounds or steroids of the present disclosure (or the prodrugs thereof), as well as the various salt forms and other pharmaceutically acceptable forms, e.g., solvates and/or hydrates of compounds described herein, and pharmaceutical compositions containing them, may in general be prepared using methods and techniques known in the art, and/or as described in the Examples provided herein.

Without wishing to be bound by any particular theory, the compounds or steroids of the present disclosure are useful for potentiating GABA at GABA_(A) receptors thereby inducing anesthesia or treating disorders related to GABA function (e.g., insomnia, mood disorders, convulsive disorders, anxiety disorders, or symptoms of ethanol withdrawal) in a subject, e.g., a human subject, and are preferably administered in the form of a pharmaceutical composition comprising an effective amount of a compound of the instant disclosure and optionally a pharmaceutically or pharmacologically acceptable carrier.

In one aspect, provided is a method of inducing anesthesia in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of one or more of the above-noted steroids, or prodrugs, or pharmaceutically acceptable salts thereof, or a pharmaceutical composition thereof.

In another aspect, provided is a method of treating disorders related to GABA function in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of one or more of the above-noted steroids, or prodrugs, or pharmaceutically acceptable salts thereof, or a pharmaceutical composition thereof. In certain embodiments, the disorder is selected from the group consisting of insomnia, mood disorders, convulsive disorders, anxiety, or symptoms of ethanol withdrawal.

In one embodiment of the present disclosure, a therapeutically effective amount of compound is from about 5 mg/kg to about 20 mg/kg, about 5 mg/kg to about 18 mg/kg, about 5 mg/kg to about 16 mg/kg, about 5 mg/kg to about 14 mg/kg, about 5 mg/kg to about 12 mg/kg, about 5 mg/kg to about 10 mg/kg, about 6 mg/kg to about 10 mg/kg, about 6 mg/kg to about 9 mg/kg, about 7 mg/kg to about 9 mg/kg, or about 8 mg/kg to about 16 mg/kg. In certain embodiments, a therapeutically effective amount of the compound is about 8 mg/kg. It will be appreciated that dose ranges as described herein provide guidance for the administration of provided pharmaceutical compositions to an adult. The amount to be administered to, for example, a child or an adolescent can be determined by a medical practitioner or person skilled in the art and can be lower or the same as that administered to an adult.

The exact amount of a compound required to achieve an effective amount will vary from subject to subject, depending, for example, on species, age, and general condition of a subject, identity of the particular compound(s), mode of administration, and the like. The desired dosage can be delivered three times a day, two times a day, once a day, every other day, every third day, every week, every two weeks, every three weeks, or every four weeks. In certain embodiments, the desired dosage can be delivered using multiple administrations (e.g., two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, or more administrations).

It will be also appreciated that a compound or composition, as described herein, can be administered in combination with one or more additional therapeutically active agents. The compounds or compositions can be administered in combination with additional therapeutically active agents that improve their bioavailability, reduce and/or modify their metabolism, inhibit their excretion, and/or modify their distribution within the body.

The compound or composition can be administered concurrently with, prior to, or subsequent to, one or more additional therapeutically active agents. In general, each agent will be administered at a dose and/or on a time schedule determined for that agent. It will further be appreciated that the additional therapeutically active agent utilized in this combination can be administered together in a single composition or administered separately in different compositions. The particular combination to employ in a regimen will take into account compatibility of the inventive compound with the additional therapeutically active agent and/or the desired therapeutic effect to be achieved. In general, it is expected that additional therapeutically active agents utilized in combination be utilized at levels that do not exceed the levels at which they are utilized individually. In some embodiments, the levels utilized in combination will be lower than those utilized individually. Exemplary therapeutically active agents include small organic molecules such as drug compounds (e.g., compounds approved by the US Food and Drug Administration as provided in the Code of Federal Regulations (CFR)), peptides, proteins, carbohydrates, monosaccharides, oligosaccharides, polysaccharides, nucleoproteins, mucoproteins, lipoproteins, synthetic polypeptides or proteins, small molecules linked to proteins, glycoproteins, steroids, nucleic acids, DNAs, RNAs, nucleotides, nucleosides, oligonucleotides, antisense oligonucleotides, lipids, hormones, vitamins and cells.

The pharmaceutical composition may also be in combination with at least one pharmacologically acceptable carrier. The carrier, also known in the art as an excipient, vehicle, auxiliary, adjuvant, or diluent, is any substance that is pharmaceutically inert, confers a suitable consistency or form to the composition, and does not diminish the therapeutic efficacy of the compounds. The carrier is “pharmaceutically or pharmacologically acceptable” if it does not produce an adverse, allergic, or other untoward reaction when administered to a mammal or human, as appropriate.

The pharmaceutical compositions containing the compounds or steroids of the present disclosure may be formulated in any conventional manner. Proper formulation is dependent upon the route of administration chosen. The compositions of the disclosure can be formulated for any route of administration, so long as the target tissue is available via that route. Suitable routes of administration include, but are not limited to, oral, parenteral (e.g., intravenous, intraarterial, subcutaneous, rectal, subcutaneous, intramuscular, intraorbital, intracapsular, intraspinal, intraperitoneal, or intrasternal), topical (nasal, transdermal, intraocular), intravesical, intrathecal, enteral, pulmonary, intralymphatic, intracavital, vaginal, transurethral, intradermal, aural, intramammary, buccal, orthotopic, intratracheal, intralesional, percutaneous, endoscopical, transmucosal, sublingual, and intestinal administration. In certain embodiments, the route of administration is oral. In certain embodiments, the route of administration is parenteral. In certain embodiments, the route of administration is intravenous.

Pharmaceutically acceptable carriers for use in the compositions of the present disclosure are well known to those of ordinary skill in the art and are selected based upon a number of factors, including for example: the particular compound used, and its concentration, stability and intended bioavailability; the disease, disorder or condition being treated with the composition; the subject, its age, size and general condition; and/or the route of administration. Suitable carriers may be readily determined by one of ordinary skill in the art. (See, for example, J. G. Nairn, in: Remington's Pharmaceutical Science (A. Gennaro, ed.), Mack Publishing Co., Easton, Pa., (1985), pp. 1492-1517.)

The compositions may be formulated as tablets, dispersible powders, pills, capsules, gelcaps, caplets, gels, liposomes, granules, solutions, suspensions, emulsions, syrups, elixirs, troches, dragees, lozenges, or any other dosage form that can be administered orally. Techniques and compositions for making oral dosage forms useful in the present disclosure are described in the following exemplary references: 7 Modern Pharmaceutics, Chapters 9 and 10 (Banker & Rhodes, Editors, 1979); Lieberman et al., Pharmaceutical Dosage Forms: Tablets (1981); and, Ansel, Introduction to Pharmaceutical Dosage Forms 2nd Edition (1976).

The compositions of the present disclosure designed for oral administration comprise an effective amount of a compound of the disclosure in a pharmaceutically acceptable carrier. Suitable carriers for solid dosage forms include sugars, starches, and other conventional substances including lactose, talc, sucrose, gelatin, carboxymethylcellulose, agar, mannitol, sorbitol, calcium phosphate, calcium carbonate, sodium carbonate, kaolin, alginic acid, acacia, corn starch, potato starch, sodium saccharin, magnesium carbonate, tragacanth, microcrystalline cellulose, colloidal silicon dioxide, croscarmellose sodium, talc, magnesium stearate, and stearic acid. Further, such solid dosage forms may be uncoated or may be coated by known techniques (e.g., to delay disintegration and absorption).

The compounds, steroids, and prodrugs of the present disclosure may also be formulated for parenteral administration (e.g., formulated for injection via intravenous, intraarterial, subcutaneous, rectal, subcutaneous, intramuscular, intraorbital, intracapsular, intraspinal, intraperitoneal, or intrasternal routes). The compositions of the present disclosure for parenteral administration comprise an effective amount of the compound in a pharmaceutically acceptable carrier. Dosage forms suitable for parenteral administration include solutions, suspensions, dispersions, emulsions or any other dosage form that can be administered parenterally. Techniques and compositions for making parenteral dosage forms are known in the art. Typically formulations for parenteral administration are sterile or are sterilized before administration.

Suitable carriers used in formulating liquid dosage forms for oral or parenteral administration include nonaqueous, pharmaceutically-acceptable polar solvents such as oils, alcohols, amides, esters, ethers, ketones, hydrocarbons and mixtures thereof, as well as water, saline solutions, dextrose solutions (e.g., DW5), electrolyte solutions, or any other aqueous, pharmaceutically acceptable liquid.

Suitable nonaqueous, pharmaceutically-acceptable polar solvents include, but are not limited to, alcohols (e.g., α-glycerol formal, β-glycerol formal, 1,3-butyleneglycol, aliphatic or aromatic alcohols having 2-30 carbon atoms such as methanol, ethanol, propanol, isopropanol, butanol, t-butanol, hexanol, octanol, amylene hydrate, benzyl alcohol, glycerin (glycerol), glycol, hexylene glycol, tetrahydrofurfuryl alcohol, lauryl alcohol, cetyl alcohol, or stearyl alcohol, fatty acid esters of fatty alcohols such as polyalkylene glycols (e.g., polypropylene glycol, polyethylene glycol), sorbitan, sucrose and cholesterol); amides (e.g., dimethylacetamide (DMA), benzyl benzoate DMA, dimethylformamide, N-(β-hydroxyethyl)-lactamide, N,N-dimethylacetamide, 2-pyrrolidinone, 1-methyl-2-pyrrolidinone, or polyvinylpyrrolidone); esters (e.g., 1-methyl-2-pyrrolidinone, 2-pyrrolidinone, acetate esters such as monoacetin, diacetin, and triacetin, aliphatic or aromatic esters such as ethyl caprylate or octanoate, alkyl oleate, benzyl benzoate, benzyl acetate, dimethylsulfoxide (DMSO), esters of glycerin such as mono, di, or tri-glyceryl citrates or tartrates, ethyl benzoate, ethyl acetate, ethyl carbonate, ethyl lactate, ethyl oleate, fatty acid esters of sorbitan, fatty acid derived PEG esters, glyceryl monostearate, glyceride esters such as mono, di, or tri-glycerides, fatty acid esters such as isopropyl myristrate, fatty acid derived PEG esters such as PEG-hydroxyoleate and PEG-hydroxystearate, N-methyl pyrrolidinone, pluronic 60, polyoxyethylene sorbitol oleic polyesters such as poly(ethoxylated)₃₀₋₆₀ sorbitol poly(oleate)₂₋₄, poly(oxyethylene)₁₅₋₂₀ monooleate, poly(oxyethylene)₁₅₋₂₀ mono 12-hydroxystearate, and poly(oxyethylene)₁₅₋₂₀ mono-ricinoleate, polyoxyethylene sorbitan esters (such as polyoxyethylene-sorbitan monooleate, polyoxyethylene-sorbitan monopalmitate, polyoxyethylene-sorbitan monolaurate, polyoxyethylene-sorbitan monostearate, and Polysorbate® 20, 40, 60 or 80 from ICI Americas, Wilmington, Del.), polyvinylpyrrolidone, alkyleneoxy modified fatty acid esters (such as polyoxyl 40 hydrogenated castor oil, cyclodextrins or modified cyclodextrins (e.g., beta-hydroxypropyl-cyclodextrin)), saccharide fatty acid esters (i.e., the condensation product of a monosaccharide (e.g., pentoses, such as ribose, ribulose, arabinose, xylose, lyxose and xylulose, hexoses such as glucose, fructose, galactose, mannose and sorbose, trioses, tetroses, heptoses, and octoses), disaccharide (e.g., sucrose, maltose, lactose and trehalose) or oligosaccharide or mixture thereof with a C₄-C₂₂ fatty acid(s)(e.g., saturated fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid and stearic acid, and unsaturated fatty acids such as palmitoleic acid, oleic acid, elaidic acid, erucic acid and linoleic acid)), or steroidal esters); alkyl, aryl, or cyclic ethers having 2-30 carbon atoms (e.g., diethyl ether, tetrahydrofuran, dimethyl isosorbide, diethylene glycol monoethyl ether); glycofurol (tetrahydrofurfuryl alcohol polyethylene glycol ether); ketones having 3-30 carbon atoms (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone); aliphatic, cycloaliphatic or aromatic hydrocarbons having 4-30 carbon atoms (e.g., benzene, cyclohexane, dichloromethane, dioxolanes, hexane, n-decane, n-dodecane, n-hexane, sulfolane, tetramethylenesulfone, tetramethylenesulfoxide, toluene, dimethylsulfoxide (DMSO), or tetramethylenesulfoxide); oils of mineral, vegetable, animal, essential or synthetic origin (e.g., mineral oils such as aliphatic or wax-based hydrocarbons, aromatic hydrocarbons, mixed aliphatic and aromatic based hydrocarbons, and refined paraffin oil, vegetable oils such as linseed, tung, safflower, soybean, castor, cottonseed, groundnut, rapeseed, coconut, palm, olive, corn, corn germ, sesame, persic and peanut oil and glycerides such as mono-, di- or triglycerides, animal oils such as fish, marine, sperm, cod-liver, haliver, squalene, squalane, and shark liver oil, oleic oils, and polyoxyethylated castor oil); alkyl or aryl halides having 1-30 carbon atoms and optionally more than one halogen substituent; methylene chloride; monoethanolamine; petroleum benzine; trolamine; omega-3 polyunsaturated fatty acids (e.g., alpha-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, or docosahexaenoic acid); polyglycol ester of 12-hydroxystearic acid and polyethylene glycol (Solutol® HS-15, from BASF, Ludwigshafen, Germany); polyoxyethylene glycerol; sodium laurate; sodium oleate; or sorbitan monooleate.

Other pharmaceutically acceptable solvents for use in the disclosure are well known to those of ordinary skill in the art, and are identified in The Handbook of Pharmaceutical Excipients, (American Pharmaceutical Association, Washington, D.C., and The Pharmaceutical Society of Great Britain, London, England, 1968), Modern Pharmaceutics, (G. Banker et al., eds., 3d ed.)(Marcel Dekker, Inc., New York, N.Y., 1995), The Pharmacological Basis of Therapeutics, (Goodman & Gilman, McGraw Hill Publishing), Pharmaceutical Dosage Forms, (H. Lieberman et al., eds.,) (Marcel Dekker, Inc., New York, N.Y., 1980), Remington's Pharmaceutical Sciences (A. Gennaro, ed., 19th ed.)(Mack Publishing, Easton, Pa., 1995), The United States Pharmacopeia 24, The National Formulary 19, (National Publishing, Philadelphia, Pa., 2000), A. J. Spiegel et al., and Use of Nonaqueous Solvents in Parenteral Products, J. of Pharm. Sciences, Vol. 52, No. 10, pp. 917-927 (1963).

Preferred solvents include cyclodextrins or modified cyclodextrins (e.g., beta-hydroxypropyl-cyclodextrin) as well as oils rich in triglycerides, for example, safflower oil, soybean oil or mixtures thereof, and alkyleneoxy modified fatty acid esters such as polyoxyl 40 hydrogenated castor oil. Commercially available triglycerides include Intralipid® emulsified soybean oil (Kabi-Pharmacia Inc., Stockholm, Sweden), Nutralipid® emulsion (McGaw, Irvine, Calif.), Liposyn® II 20% emulsion (a 20% fat emulsion solution containing 100 mg safflower oil, 100 mg soybean oil, 12 mg egg phosphatides, and 25 mg glycerin per ml of solution; Abbott Laboratories, Chicago, Ill.), Liposyn® III 2% emulsion (a 2% fat emulsion solution containing 100 mg safflower oil, 100 mg soybean oil, 12 mg egg phosphatides, and 25 mg glycerin per ml of solution; Abbott Laboratories, Chicago, Ill.), natural or synthetic glycerol derivatives containing the docosahexaenoyl group at levels between 25% and 100% by weight based on the total fatty acid content (Dhasco® (from Martek Biosciences Corp., Columbia, Md.), DHA Maguro® (from Daito Enterprises, Los Angeles, Calif.), Soyacal®, and Travemulsion®.

Additional minor components can be included in the compositions of the disclosure for a variety of purposes well known in the pharmaceutical industry. These components will for the most part impart properties which enhance retention of the compound at the site of administration, protect the stability of the composition, control the pH, facilitate processing of the compound into pharmaceutical formulations, and the like. Preferably, each of these components is individually present in less than about 15 wt % of the total composition, more preferably less than about 5 wt %, and most preferably less than about 0.5 wt % of the total composition. Some components, such as fillers or diluents, can constitute up to 90 wt % of the total composition, as is well known in the formulation art. Such additives include cryoprotective agents for preventing reprecipitation, surface active, wetting or emulsifying agents (e.g., lecithin, polysorbate-80, Tween® 80, Pluronic 60, polyoxyethylene stearate), preservatives (e.g., ethyl-p-hydroxybenzoate), microbial preservatives (e.g., benzyl alcohol, phenol, m-cresol, chlorobutanol, sorbic acid, thimerosal and paraben), agents for adjusting pH or buffering agents (e.g., acids, bases, sodium acetate, sorbitan monolaurate), agents for adjusting osmolarity (e.g., glycerin), thickeners (e.g., aluminum monostearate, stearic acid, cetyl alcohol, stearyl alcohol, guar gum, methyl cellulose, hydroxypropylcellulose, tristearin, cetyl wax esters, polyethylene glycol), colorants, dyes, flow aids, non-volatile silicones (e.g., cyclomethicone), clays (e.g., bentonites), adhesives, bulking agents, flavorings, sweeteners, adsorbents, fillers (e.g., sugars such as lactose, sucrose, mannitol, or sorbitol, cellulose, or calcium phosphate), diluents (e.g., water, saline, electrolyte solutions), binders (e.g., starches such as maize starch, wheat starch, rice starch, or potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, polyvinylpyrrolidone, sugars, polymers, acacia), disintegrating agents (e.g., starches such as maize starch, wheat starch, rice starch, potato starch, or carboxymethyl starch, cross-linked polyvinyl pyrrolidone, agar, alginic acid or a salt thereof such as sodium alginate, croscarmellose sodium or crospovidone), lubricants (e.g., silica, talc, stearic acid or salts thereof such as magnesium stearate, or polyethylene glycol), coating agents (e.g., concentrated sugar solutions including gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, or titanium dioxide), and antioxidants (e.g., sodium metabisulfite, sodium bisulfate, sodium sulfite, dextrose, phenols, and thiophenols).

Dosage from administration by these routes may be continuous or intermittent, depending, for example, upon the patient's physiological condition, whether the purpose of the administration is therapeutic or prophylactic, and other factors known to and assessable by a skilled practitioner.

Those with ordinary skill in administering anesthetics can readily determine dosage and regimens for the administration of the pharmaceutical compositions of the disclosure or titrating to an effective dosage for use in treating insomnia, mood disorders, convulsive disorders, anxiety or symptoms of ethanol withdrawal. It is understood that the dosage of the compounds will be dependent upon the age, sex, health, and weight of the recipient, kind of concurrent treatment, if any, frequency of treatment, and the nature of the effect desired. For any mode of administration, the actual amount of compound delivered, as well as the dosing schedule necessary to achieve the advantageous effects described herein, will also depend, in part, on such factors as the bioavailability of the compound, the disorder being treated, the desired therapeutic dose, and other factors that will be apparent to those of skill in the art. The dose administered to an animal, particularly a human, in the context of the present disclosure should be sufficient to affect the desired therapeutic response in the animal over a reasonable period of time. Preferably, an effective amount of the compound, whether administered orally or by another route, is any amount that would result in a desired therapeutic response when administered by that route. The dosage may vary depending on the dosing schedule, which can be adjusted as necessary to achieve the desired therapeutic effect. The most preferred dosage will be tailored to the individual subject, as is understood and determinable by one of ordinary skill in the art without undue experimentation.

In one embodiment, solutions for oral administration are prepared by dissolving the compound in any pharmaceutically acceptable solvent capable of dissolving a compound (e.g., ethanol or methylene chloride) to form a solution. An appropriate volume of a carrier which is a solution, such as beta-hydroxypropyl-cyclodextrin, is added to the solution while stirring to form a pharmaceutically acceptable solution for oral administration to a patient. If desired, such solutions can be formulated to contain a minimal amount of, or to be free of, ethanol, which is known in the art to cause adverse physiological effects when administered at certain concentrations in oral formulations.

In another embodiment, powders or tablets for oral administration are prepared by dissolving a compound in any pharmaceutically acceptable solvent capable of dissolving the compound (e.g., ethanol or methylene chloride) to form a solution. The solvent can optionally be capable of evaporating when the solution is dried under vacuum. An additional carrier can be added to the solution prior to drying, such as beta-hydroxypropyl-cyclodextrin. The resulting solution is dried under vacuum to form a glass. The glass is then mixed with a binder to form a powder. The powder can be mixed with fillers or other conventional tabletting agents and processed to form a tablet for oral administration to a patient. The powder can also be added to any liquid carrier as described above to form a solution, emulsion, suspension or the like for oral administration.

Emulsions for parenteral administration can be prepared by dissolving a compound in any pharmaceutically acceptable solvent capable of dissolving the compound (e.g., ethanol or methylene chloride) to form a solution. An appropriate volume of a carrier which is an emulsion, such as Liposyn® II or Liposyn® III emulsions, is added to the solution while stirring to form a pharmaceutically acceptable emulsion for parenteral administration to a patient.

Solutions for parenteral administration can be prepared by dissolving a compound in any pharmaceutically acceptable solvent capable of dissolving the compound (e.g., ethanol or methylene chloride) to form a solution. An appropriate volume of a carrier which is a solution, such as beta-hydroxypropyl-cyclodextrin, is added to the solution while stirring to form a pharmaceutically acceptable solution for parenteral administration to a patient.

If desired, the emulsions or solutions described above for oral or parenteral administration can be packaged in IV bags, vials or other conventional containers in concentrated form and diluted with any pharmaceutically acceptable liquid, such as saline, to form an acceptable concentration prior to use as is known in the art.

Still further encompassed by the invention are kits (e.g., pharmaceutical packs). The kits provided may comprise a compound as described herein and a container (e.g., a vial, ampule, bottle, syringe, and/or dispenser package, or other suitable container). In some embodiments, provided kits may optionally further include a second container comprising a pharmaceutical carrier for dilution or suspension of the pharmaceutical composition or compound. In some embodiments, the pharmaceutical composition or compound provided in the container and the second container are combined to form one unit dosage form.

Optionally, instructions for use are additionally provided in such kits of the invention. Such instructions may provide, generally, for example, instructions for dosage and administration. In other embodiments, instructions may further provide additional detail relating to specialized instructions for particular containers and/or systems for administration. Still further, instructions may provide specialized instructions for use in conjunction and/or in combination with an additional therapeutic agent.

4. Definitions

The term “steroid” as used herein describes an organic compound containing in its chemical nucleus the cyclopenta[a]phenanthrene ring system.

As used herein, the term “pharmaceutically acceptable salt” refers to those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, Berge et al., describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 1977, 66, 1-19. Pharmaceutically acceptable salts of the compounds of this invention include those derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. Salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N⁺(C₁₋₄alkyl)₄ salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, lower alkyl sulfonate and aryl sulfonate.

The term “prodrug” as used herein describes a pharmacological substance that is administered in a less active or inactive form. After administration, a prodrug is metabolized in vivo e.g., via hydrolysis, oxidation, or reaction under biological conditions (in vitro or in vivo), to provide an active metabolite. See, e.g., Wu, Pharmaceuticals (2009) 2:77-81. In certain embodiments, a prodrug has improved physical and/or delivery properties over the parent compound. Prodrugs are typically designed to enhance pharmaceutically and/or pharmacokinetically based properties associated with the parent compound. The advantage of a prodrug can lie in its physical properties, such as enhanced water solubility for parenteral administration at physiological pH compared to the parent compound, or it enhances absorption from the digestive tract or the skin, or it may enhance drug stability for long-term storage.

As used herein, a “subject” to which administration is contemplated includes, but is not limited to, mammals, e.g., humans (i.e., a male or female of any age group, e.g., a pediatric subject (e.g., child, adolescent) or adult subject (e.g., young adult, middle-aged adult or senior adult)), other primates (e.g., cynomolgus monkeys, rhesus monkeys) and commercially relevant mammals such as cattle, pigs, horses, sheep, goats, cats, and/or dogs. In any aspect and/or embodiment of the invention, the subject is a human.

As used herein, a “therapeutically effective amount”, “an amount sufficient” or “sufficient amount” of a compound means the level, amount or concentration of the compound required for a desired biological response, e.g., analgesia.

The term “saturated” as used herein describes the state in which all available valence bonds of an atom (especially carbon) are attached to other atoms.

The term “unsaturated” as used herein describes the state in which not all available valence bonds along the alkyl chain are satisfied; in such compounds the extra bonds usually form double or triple bonds (chiefly with carbon).

When a range of values is listed, it is intended to encompass each value and sub-range within the range. For example “C₁ alkyl” is intended to encompass, C₁, C₂, C₃, C₄, C₁₋₃, C₁₋₂, C₂₋₄, C₂₋₃ and C₃₋₄ alkyl, while “C₁₋₂₂ alkyl” is intended to encompass, for example, C₁, C₂, C₃, C₄, etc., as well as C₁₋₂₁, C₁₋₂₀, C₁₋₁₅, C₁₋₁₀, C₂₋₂₀, C₂₋₁₅, C₂₋₁₀, C₃₋₁₅, C₃₋₁₀, etc. alkyl.

As used herein, “alkyl” refers to a radical of a straight-chain or branched saturated hydrocarbon group having from, in some embodiments, 1 to 4 carbon atoms (“C₁ alkyl”), and in other embodiments 1 to 22 carbon atoms (“C₁₋₂₂ alkyl”). In some embodiments, an alkyl group has 1 to 3 carbon atoms (“C₁₋₃ alkyl”). In some embodiments, an alkyl group has 1 to 2 carbon atoms (“C₁₋₂ alkyl”). In some embodiments, an alkyl group has 1 carbon atom (“C₁ alkyl”). In some embodiments, an alkyl group has 2 to 4 carbon atom (“C₂₋₄ alkyl”). In yet other embodiments, an alkyl group has 1 to 21 carbon atoms (“C₁₋₂₁ alkyl”), 1 to 20 carbon atoms (“C₁₋₂₀ alkyl”), 1 to 15 carbon atoms (“C₁₋₁₅ alkyl”), 1 to 10 carbon atoms (“C₁₋₁₀ alkyl”), etc. Examples of such alkyl groups include methyl (C₁), ethyl (C₂), n-propyl (C₃), isopropyl (C₃), n-butyl (C₄), tert-butyl (C₄), sec-butyl (C₄), iso-butyl (C₄), pentyl (C₅), and the like.

As used herein, “alkenyl” or “alkene” refers to a radical of a straight-chain or branched hydrocarbon group having from, in some embodiments, 2 to 4 carbon atoms (“C₂ alkenyl”), and in other embodiments 2 to 22 carbon atoms (“C₂₋₂₂ alkenyl”), and one or more carbon-carbon double bonds. In some embodiments, an alkenyl group has 2 to 3 carbon atoms (“C₂₋₃ alkenyl”). In some embodiments, an alkenyl group has 2 carbon atoms (“C₂ alkenyl”). In yet other embodiments, an alkenyl group has 2 to 21 carbon atoms (“C₂₋₂₁ alkenyl”), 2 to 20 carbon atoms (“C₂₋₂₀ alkenyl”), 2 to 15 carbon atoms (“C₂₋₁₅ alkenyl”), 2 to 10 carbon atoms (“C₂₋₁₀ alkyl”), etc. The one or more carbon-carbon double bonds can be internal (such as in 2-butenyl) or terminal (such as in 1-butenyl). Examples of such alkenyl groups include ethenyl (C₂), 1-propenyl (C₃), 2-propenyl (C₃), 1-butenyl (C₄), 2-butenyl (C₄), butadienyl (C₄), 1-pentenyl (C₅), 2-pentenyl (C₅), and the like.

As used herein, “alkynyl” or “alkyne” refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 4 carbon atoms and one or more carbon-carbon triple bonds (“C₂₋₁₀ alkynyl”). In some embodiments, an alkynyl group has 2 to 3 carbon atoms (“C₂₋₃ alkynyl”). In some embodiments, an alkynyl group has 2 carbon atoms (“C₂ alkynyl”). The one or more carbon-carbon triple bonds can be internal (such as in 2-butynyl) or terminal (such as in 1-butynyl). Examples of C₂ alkynyl groups include, without limitation, ethynyl (C₂), 1-propynyl (C₃), 2-propynyl (C₃), 1-butynyl (C₄), 2-butynyl (C₄), and the like.

As used herein, “aryl” refers to a radical of a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 electrons shared in a cyclic array) having 6-14 ring carbon atoms and zero heteroatoms provided in the aromatic ring system (“C₆₋₁₄ aryl”). In some embodiments, an aryl group has 6 ring carbon atoms (“C₆ aryl”; e.g., phenyl). In some embodiments, an aryl group has 10 ring carbon atoms (“C₁₀ aryl”; e.g., naphthyl such as 1-naphthyl and 2-naphthyl). In some embodiments, an aryl group has 14 ring carbon atoms (“C₁₄ aryl”; e.g., anthracyl).

As used herein, “alkoxy” refers to an alkyl, alkenyl, or alkynyl group, as defined herein, attached to an oxygen radical.

Alkyl, alkenyl, alkynyl, and aryl groups, as defined herein, are substituted or unsubstituted, also referred to herein as “optionally substituted”. In general, the term “substituted”, whether preceded by the term “optionally” or not, means that at least one hydrogen present on a group (e.g., a carbon or nitrogen atom) is replaced with a permissible substituent, e.g., a substituent which upon substitution results in a stable compound, e.g., a compound which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, or other reaction. Unless otherwise indicated, a “substituted” group has a substituent at one or more substitutable positions of the group, and when more than one position in any given structure is substituted, the substituent is either the same or different at each position. The term “substituted” is contemplated to include substitution with all permissible substituents of organic compounds, any of the substituents described herein that result in the formation of a stable compound. The present invention contemplates any and all such combinations in order to arrive at a stable compound. For purposes of this invention, heteroatoms such as nitrogen may have hydrogen substituents and/or any suitable substituent as described herein which satisfy the valencies of the heteroatoms and results in the formation of a stable moiety.

Exemplary substituents include groups that contain a heteroatom (such as nitrogen, oxygen, silicon, phosphorous, boron, sulfur, or a halogen atom), halogen (e.g., chlorine, bromine, fluorine, or iodine), a heterocycle, alkoxy, alkenoxy, alkynoxy, aryloxy, hydroxy, protected hydroxy, keto, acyl, acyloxy, nitro, amino, amido, nitro, cyano, thiol, ketals, acetals, esters and ethers.

EXAMPLES

The following Examples describe or illustrate various embodiments of the present disclosure. Other embodiments within the scope of the appended claims will be apparent to a skilled artisan considering the specification or practice of the disclosure as described herein. It is intended that the specification, together with the Examples, be considered exemplary only, with the scope and spirit of the disclosure being indicated by the claims, which follow the Example.

A. Compound Chemistry

In accordance with the following methods and Examples, the following compounds were prepared for purposes of illustration:

In accordance with Scheme 1, the following compounds were prepared, using methods generally known in the art and as outlined below.

19-[[(1,1-Dimethyl)dimethylsilyl]oxy]-androst-4-ene-3,17-dione (1)

A mixture of the known 19-hydroxyandrostenedione (1 g, 3.31 mmol), tert-butyldimethylsilyl chloride (602 mg, 4 mmol), imidazole (315 mg, 4.63 mmol), DMF (5 mL) and methylene chloride (5 mL) was stirred at room temperature for 15 h. Water (100 mL) was added to the reaction mixture and extracted with methylene chloride (50 mL×3). The combined organic extracts were washed with brine, dried and concentrated to give a white solid. The solid was purified by flash column chromatography (silica gel eluted with 10-20% EtOAc in hexanes) to give a white solid (1.3 g, 94%): mp 154-156° C.; IR 2856, 2930, 1739, 1670, 1472, 1359, 1255, 1228 cm⁻¹; ¹H NMR (CDCl₃) δ 5.85 (s, 1H), 3.87 (dd, J=12.9, 10.0 Hz, 2H), 2.65-0.95 (m), 0.89 (s, 3H), 0.83 (s, 9H), 0.03 (s, 3H), 0.02 (s, 3H); ¹³C NMR (CDCl₃) δ 220.0, 199.6, 167.2, 126.0, 65.8, 54.0, 51.3, 47.5, 43.5, 35.9, 35.6, 34.6, 33.5, 33.2, 31.7, 30.7, 25.7 (3×C), 21.6, 20.9, 18.0, 13.8, −5.76, −5.83.

(5α)-19-[[(Dimethylethyl)dimethylsilyl]oxy]-androstane-3,17-dione (2)

Lithium wire in small pieces (140 mg, 20 mmol) was added to a stirred cold solution (−78° C.) of freshly condensed liquid ammonia (250 mL) and the mixture was stirred for 15 min. Steroid 1 (1.25 g, 3 mmol) in THF (75 mL) was added to the resulting deep blue solution and stirring was continued at −78° C. for 2 h. Solid ammonium chloride (5 g) was added and the ammonia was allowed to evaporate. Water (200 mL) was added and the reaction mixture was extracted with EtOAc (100 mL×3). The combined EtOAc extracts were washed with brine, dried and concentrated to give an oil. The oil was dissolved in stirred acetone (50 mL) and cooled in an ice bath. Jones reagent was added to the stirred cold solution until an orange color persisted for 1 h. The excess Jones reagent was reduced by adding few drops of isopropyl alcohol. The acetone was removed under reduced pressure and the resulting solution was diluted with water (200 mL) and extracted with EtOAc (80 mL×3). The combined EtOAc extracts were dried and removed to give a white solid which was purified by chromatography (silica gel) to yield steroid 2 (830 mg, 63%): mp 130-132° C.; IR 3339, 2922, 2857, 1445, 1360 cm⁻¹; ¹H NMR (CDCl₃) δ 3.87 (dd, J=21.2, 10.0 Hz, 2H), 2.60-0.70 (m), 0.87 (s, 9H), 0.07 (s, 3H), 0.06 (s, 3H); ¹³C NMR (CDCl₃) δ 220.6, 211.8, 60.9, 54.3, 51.6, 47.7, 46.1, 44.8, 39.4, 38.5, 35.7, 35.4, 33.9, 31.9, 30.5, 28.3, 25.7 (3×C), 21.7, 18.0, 13.8, −5.7, −5.9.

(5α)-19-[[(Dimethylethyl)dimethylsilyl]oxy]-androstane-3,17-dione, 3-cyclic 1,2-ethandiyl acetal (3)

A solution of steroid 2 (4.6 g, 11.0 mmol) in benzene (˜100 mL) containing ethylene glycol (5 mL) and PPTS (500 mg) was heated under reflux with Dean-Stark apparatus for 4 h. The solvent was removed under reduced pressure and the residue was purified by column chromatography (silica gel eluted with 20% EtOAc in hexanes) to give the 3.17-bisketal (3.5 g) and steroid 3 as a solidified foam (1.25 g): ¹H NMR (CDCl₃) δ 3.85-3.90 (m, 4H), 3.81 (d, J=10.6 Hz, 1H), 3.65 (d, J=10.6 Hz, 1H), 2.36-0.76 (m), 0.83 (s, 9H), 0.10 (d, J=3.9 Hz, 6H); ¹³C NMR (CDCl₃) δ 221.2, 109.1, 64.1, 60.3, 59.9, 54.5, 51.8, 47.8, 43.6, 39.2, 38.3, 35.7, 35.4, 32.0, 31.3, 30.7, 30.6, 27.8, 25.7, 21.7, 20.9, 17.0, 14.1, −5.7, −5.9; Anal. Calcd for C₂₇H₄₆O₄Si: C, 70.08; H, 10.02. Found: C, 69.89; H, 10.0.

(5α)-19-Hydroxyandrostane-3,17-dione, 3-cyclic 1,2-ethandiyl acetal (4)

To a solution of steroid 3 (1.0 g, 2.4 mmol) in THF (10 mL) was added TBAF (6.0 mmol, 1.0 M in THF, 6.0 mL) at room temperature. The reaction mixture was refluxed for 16 h and the solvent was removed under reduced pressure and the residue was purified by column chromatography (silica gel eluted with 30% EtOAc in hexanes) to give steroid 4 as an oil (638 mg, 84%): IR ν_(max) 3487, 1738 cm⁻¹; ¹H NMR (CDCl₃) δ 3.90-3.85 (m, 4H), 3.86 (d, J=11.4 Hz, 1H), 3.78 (d, J=11.4 Hz, 1H), 2.42-0.76 (m), 0.86 (s, 3H); ¹³C NMR (CDCl₃) δ 221.4, 108.9, 64.1, 64.0, 60.0, 54.4, 51.6, 47.8, 43.7, 39.2, 38.2, 35.7, 35.4, 31.9, 31.4, 30.6, 30.1, 27.7, 21.9, 21.7, 13.9.

(5α,17β)-17,17-Dihydroxyandrostan-3-one, cyclic 1,2-ethandiyl acetal (5)

To a solution of steroid 4 (635 mg, 1.8 mmol) in ethanol (40 mL) was added sodium borohydride (152 mg, 4 mmol) at room temperature. After 3 h, the mixture was quenched by aqueous NH₄Cl. The mixture was extracted with EtOAc (50 mL×3), the organic layers were combined and dried over MgSO₄, filtered, and concentrated. The residue was purified by column chromatography (silica gel eluted with 35% EtOAc in hexanes) to give steroid 5 as an oil (638 mg, 100%): ¹H NMR (CDCl₃) δ 3.92-3.90 (m, 5H), 3.90 (d, J=12.4 Hz, 1H), 3.61 (t, J=8.6 Hz, 1H), 2.22-0.73 (m), 0.76 (s, 3H); ¹³C NMR (CDCl₃) δ 109.1, 81.8, 64.2, 64.1, 60.2, 54.4, 51.3, 43.8, 43.1, 39.3, 38.3, 37.2, 36.0, 31.6, 31.3, 30.4, 30.1, 27.9, 23.4, 22.5, 11.4.

(5α,17β)-17,19-Dimethoxyandrostan-3-one, cyclic 1,2-ethandiyl acetal (6)

To a solution of steroid 5 (635 mg, 1.8 mmol) in THF (30 mL) was added sodium hydride (400 mg, 60% in mineral oil, 6.0 mmol). After addition, the mixture was refluxed for 1 h, iodomethane was added and refluxed for an additional 3 h. After cooling down to room temperature, the mixture was quenched by water and extracted with EtOAc (100 mL×3). The organic extracts were combined and dried over with MgSO₄, filtered, and concentrated. The residue was purified by column chromatography (silica gel eluted with 20% EtOAc in hexanes) to give steroid 6 (623 mg, 92%): mp 102-104° C.; IR ν_(max) 2922, 1448 cm⁻¹; ¹H NMR (CDCl₃) δ 3.84 (m, 4H), 3.43 (d, J=9.4 Hz, 1H), 3.36 (d, J=9.4 Hz, 1H), 3.24 (s, 3H), 3.21 (s, 3H), 3.12 (t, J=7.8 Hz, 1H), 2.10-0.63 (m), 0.68 (3H); ¹³C NMR (CDCl₃) δ 109.1, 90.6, 70.9, 64.0 (2×C), 58.9, 57.6, 54.2, 51.3, 43.7, 42.9, 38.8, 38.3, 38.2, 35.6, 31.4, 31.3, 30.9, 28.0, 27.5, 23.2, 21.9, 11.5.

(5α,17β)-17,19-Dimethoxyandrostan-3-one (7, MQ-88)

The mixture of steroid 6 (625 mg, 1.65 mmol), PTSA (100 mg), acetone (30 ml) and water (3 mL) was stirred at room temperature for 16 h. Solvents were removed by reduced pressure, aqueous NaHCO₃ was added and the product extracted into EtOAc (100 mL×3). The organic layers were combined, dried over with MgSO₄, filtered, and concentrated. The residue was purified by column chromatography (silica gel eluted with 20% EtOAc in hexanes) to give steroid 7 (408 mg, 74%): mp 91-93° C.; [α]_(D) ²⁰=18.4 (c=0.37, CHCl₃); ν_(max) 2922, 1714 cm⁻¹; ¹H NMR (CDCl₃) δ 3.60 (d, J=10.2 Hz, 1H), 3.55 (d, J=9.7 Hz, 1H), 3.24 (s, 6H), 3.12 (t, J=8.2 Hz, 1H), 2.45-0.64 (m), 0.70 (s, 3H); ¹³C NMR (CDCl₃) δ 212.1, 90.4, 71.8, 59.0, 57.6, 54.0, 51.2, 46.3, 44.8, 42.8, 38.8, 38.7, 38.0, 35.5, 34.3, 31.0, 28.3, 27.5, 23.1, 21.8, 11.5. Anal. Calcd for C₂₁H₃₄O₃: C, 75.41; H, 10.25. Found: C, 75.37; H, 10.13.

(5α,17β)-17,19-Dimethoxyandrostan-3-ol (8, MQ-89)

To a solution of steroid 7 (200 mg, 0.60 mmol) in THF (10 mL) was added K-Selectride® (1.0 mmol, 1.0 M in THF, 1.0 mL) at −78° C. After 2 h, 3 N NaOH (10 mL) and H₂O₂ (5 mL) were added at −78° C. and the reaction was allowed to warm up to room temperature for 1 h. The product was extracted into EtOAc (100 mL×2) and washed with brine. The organic layers were combined and dried over MgSO₄, filtered, and concentrated. The residue was purified by column chromatography (silica gel eluted with 20% EtOAc in hexanes) to give steroid 8 (172 mg, 86%): mp 62-64° C.; [α]_(D) ²°=1.1 (c=0.26, CHCl₃); ν_(max) 3382, 1447 cm⁻¹; ¹H NMR (CDCl₃) δ 4.10-4.05 (m, 1H), 3.50 (d, J=10.2 Hz, 1H), 3.42 (d, J=9.8 Hz, 1H), 3.33 (s, 3H), 3.29 (s, 3H), 3.23 (t, J=8.2, 1H), 2.01-0.80 (m), 0.76 (s, 3H); ¹³C NMR (CDCl₃) δ 90.9, 71.1, 66.4, 59.1, 57.8, 54.7, 51.6, 43.0, 39.6, 39.3, 38.5, 36.2, 35.8, 31.5, 29.5, 28.1, 27.7, 27.0, 23.3, 21.7, 11.7. Anal. Calcd for C₂₁H₃₆O₃: C, 74.95; H, 10.78. Found: C, 75.19; H, 10.79.

(5α)-19-Methoxyandrostane-3,17-dione, cyclic bis-(1,2-ethanediyl acetal) (9)

A mixture of the known (5α)-19-hydroxyandrostane-3,17-dione, cyclic bis-(1,2-ethanediyl) acetal (430 mg, 1.1 mmol), NaH (200 mg, 5 mmol) and THF (10 mL) was heated at reflux for 2 h under N₂. The reaction mixture was cooled to room temperature, and methyl iodide (2 mL, 32 mmol) was added and the mixture was stirred at room temperature for 13 h. The reaction mixture was cooled to 0° C. and excess NaH was carefully quenched by adding MeOH (2 mL). Water (100 mL) was added and the product was extracted into EtOAc (80 mL×3). The combined organic extracts were washed with brine, dried and concentrated to give a colorless liquid. The crude product was purified by flash column chromatography (silica gel eluted with 15-20% EtOAc in hexanes) to give the product as a colorless liquid (440 mg, 99%): IR ν_(max) 2923, 1457, 1378, 1306, 1210 cm⁻¹; ¹H NMR δ 3.89 (s, 4H), 3.87-3.82 (m, 4H), 3.47 (d, J=10.0 Hz, 1H), 3.39 (d, J=9.9 Hz, 1H), 3.25 (s, 3H), 2.20-0.85 (m), 0.82 (s, 3H); ¹³C NMR δ 119.3, 109.2, 71.0, 65.0, 64.5, 64.0, 59.0, 54.0, 50.4, 46.0, 43.8, 38.9, 38.4, 36.2, 34.1, 31.5, 31.1, 31.0 (2×C), 29.6, 28.1, 22.6, 21.7, 14.4. Anal. Calcd for: C₂₄H₃₈O₅: C, 70.90%; H, 9.42%. Found: C, 71.17%; H, 9.53%.

(5α)-19-Methoxyandrostane-3,17-dione (10)

A mixture of steroid 9 (400 mg, 0.98 mmol), PTSA (100 mg), acetone (8 mL) and water (0.5 mL) was stirred at room temperature for 14 h. The reaction was neutralized with aqueous NaHCO₃ and the acetone was removed under reduced pressure. Water (80 mL) was added and the product was extracted into EtOAc (60 mL×3). The combined EtOAc extracts were dried and concentrated to give a white solid which was purified by flash column chromatography (silica gel eluted with 20-30% EtOAc in hexanes) to yield product 10 (230 mg, 73%): mp 94-96° C.; IR ν_(max) 2918, 1738, 1712, 1452, 1407, 1373, 1270, 1248, 1220, 1202, cm⁻¹; ¹H NMR δ 3.60 (d, J=11.0 Hz, 1H), 3.57 (d, J=11.0 Hz, 1H), 3.26 (s, 3H), 2.50-0.74 (m), 0.82 (s, 3H); ¹³C NMR δ 220.5, 211.7, 71.7, 59.0, 53.9, 51.3, 47.6, 46.1, 44.7, 38.9, 38.5, 35.6, 35.3, 34.2, 31.5, 30.3, 28.1, 21.5, 21.3, 13.7. HRMS Calcd for C₂₀H₃₀O₃: 318.2195. Found: 318.2180.

(3α,5α)-3-Hydroxy-19-methoxyandrostan-17-one (11, KK-125)

A 1 M K-Selectride® solution in THF (2 mL, 2 mmol, 3 eq) was added to a cold solution (−78° C.) of steroid 10 (210 mg, 0.66 mmol) in THF (5 mL) and the reaction was stirred at −78° C. for 1.5 h. The reaction was quenched by adding a few drops of acetone and then allowed to warm to room temperature. 3 N aqueous NaOH (10 mL) followed by 30% aqueous H₂O₂ (10 mL) was added and the reaction was stirred at room temperature for 1.5 h. The product was extracted into EtOAc (3×60 mL) and the combined EtOAc extracts were washed with brine, dried, and concentrated to give an off-white solid which was purified by flash column chromatography (silica gel eluted with 20-40% EtOAc in hexanes). Product 11 (142 mg, 67%) had: mp 172-174° C.; IR ν_(max) 3436, 2921, 1738, 1453, 1406, 1372, 1248, 1203 cm⁻¹; ¹H NMR δ 4.05 (b s, 1H), 3.48 (d, J=9.9 Hz, 1H), 3.38 (d, J=10.2 Hz, 1H), 3.25 (s, 3H), 2.39 (dd, J=19.3, 8.8 Hz, 1H), 2.2.10-0.70 (m), 0.84 (s, 3H); ¹³C NMR δ 221.5, 71.1, 66.1, 59.0, 54.6, 51.7, 47.8, 39.6, 39.2, 36.0, 35.7, 35.5, 31.8, 30.7, 29.2, 27.9, 27.1, 21.6, 21.1, 13.8. Anal. Calcd for C₂₀H₃₂O₃: C, 74.96%; H, 10.06%. Found: C, 74.91%; H, 9.86%.

(3α,5α,17β)-19-Methoxyspiro[androstane-17,2′-oxiran]-3-ol (12, MQ-90)

To a solution of steroid 11 (100 mg, 0.3 mmol) in DMF (10 mL) was added trimethylsulfonium iodide (306 mg, 1.5 mmol) and potassium tert-butoxide (168 mg, 1.5 mmol) at room temperature. The reaction was quenched by aqueous NH₄Cl after 2 h. The mixture was extracted with dichloromethane (100 mL×2) and washed with brine. The organic layers were combined and dried over MgSO₄, filtered, and concentrated. The residue was purified by column chromatography (silica gel eluted with 25% EtOAc in hexanes) to give steroid 12 (76 mg, 75%): mp 168-170° C.; [α]_(D) ²⁰=−3.1 (c=0.16, CHCl₃); ν_(max) 3420, 1445 cm⁻¹; ¹H NMR (CDCl₃) δ 4.10-4.05 (m, 1H), 3.51 (d, J=10.2 Hz, 1H), 3.42 (d, J=10.2 Hz, 1H), 3.29 (s, 3H), 2.90 (d, J=5.1 Hz, 1H), 2.60 (d, J=5.0 Hz, 1H), 2.00-0.77 (m), 0.89 (s, 3H); ¹³C NMR (CDCl₃) δ 71.0, 70.6, 66.4, 59.1, 54.6, 53.6, 53.1, 40.2, 39.6, 39.3, 36.2, 36.1, 34.3, 31.4, 29.4, 29.0, 28.1, 27.1, 23.5, 21.4, 14.4. Anal. Calcd for C₂₁H₃₄O₃: C, 75.41; H, 10.25. Found: C, 75.44; H, 9.98.

(3α,5α)-19-Methoxy-3-(methoxymethoxy)-androstan-17-one (13)

To a solution of steroid 11 (800 mg, 2.5 mmol) in DCM (20 mL) was added chloromethyl methyl ether (302 mg, 3.75 mmol) and N,N-diisopropylethylamine (774 mg, 6 mmol) at room temperature. The mixture was quenched by water after 16 h and extracted with EtOAc (100 mL×2) and washed with brine. The organic layers were dried over with MgSO₄, filtered, and concentrated. The residue was purified by column chromatography (silica gel eluted with 25% EtOAc in hexanes) to give product 13 as an oil (900 mg, 100%): IR ν_(max) 2921, 1740 cm⁻¹; ¹H NMR (CDCl₃) δ 4.65 (q, J=6.6, 10.9, 1H), 3.86-3.84 (m, 1H), 3.52 (d, J=10.2 Hz, 1H), 3.43 (d, J=9.8 Hz, 1H), 3.35 (s, 3H), 3.28 (s, 3H), 2.44-0.83 (m), 0.86 (s, 3H); ¹³C NMR (CDCl₃) δ 221.4, 94.5, 71.3, 71.2, 59.1, 55.1, 54.6, 51.7, 47.9, 39.9, 39.4, 35.8, 35.5, 34.0, 31.9, 30.8, 28.0, 27.7, 26.5, 21.7, 21.2, 13.9.

(3α,5α)-19-Methoxy-3-(methoxymethoxy)-androst-16-ene-17-carbonitrile (14)

To a solution of steroid 13 (800 mg, 2.5 mmol) in THF (20 mL) was added potassium bis(trimethylsilyl)amide (3.0 mmol, 0.5 M in toluene, 6.0 mL) at −78° C. After 30 min, N-phenyltrifluoromethanesulfonimide (1.07 g, 3.0 mmol) in 5 mL of THF was added at −78° C. After 2 h at −78° C., the mixture was quenched by water and extracted with EtOAc (50 mL×3). The combined organic layers were dried, filtered, and concentrated. The residue was purified by flash chromatography (silia gel) to afford the intermediate enol triflate (1.21 g containing an inseparable impurity). To the enol triflate (1.21 g) in a 50 mL round flask was added sodium cyanide (300 mg, 6.0 mmol), copper (I) iodide (120 mg, 0.6 mmol) and Pd(PPh₃)₄ (60 mg) at room temperature. Acetonitrile (25 mL) was added and the mixture was refluxed for 3 h. The mixture was quenched by aqueous NH₄Cl and extracted with EtOAc (50 mL×3). The combined organic layers were dried, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 10% EtOAc in hexanes) to afford product 14 as an oil (886 mg containing an inseparable impurity): ¹H NMR (CDCl₃) δ 6.54-6.53 (m, 1H), 4.62 (q, J=7.0, 9.8 Hz, 2H), 3.80-3.70 (m, 1H), 3.47 (d, J=9.8 Hz, 1H), 3.39 (d, J=10.2 Hz, 1H), 3.30 (s, 3H), 3.23 (s, 3H), 2.29-0.82 (m), 0.85 (s, 3H); ¹³C NMR (CDCl₃) δ 147.7, 127.3, 116.0, 94.4, 71.5, 71.3, 59.1, 56.2, 55.0, 54.8, 48.4, 39.9, 39.5, 34.3, 34.2, 33.8, 32.8, 31.6, 27.9, 27.4, 26.4, 21.5, 16.3.

(3α,5α)-3-Hydroxy-19-methoxyandrost-16-ene-17-carbonitrile (15, MQ-91)

To steroid 14 containing an inseparable impurity (886 mg) in methanol (20 mL) was added 6 N HCl (15 ml) at room temperature. After 14 h, the mixture was extracted with dichloromethane (50 mL×2). The combined organic layers were dried, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 30% EtOAc in hexanes) to afford product 15 (480 mg, 58% yield from steroid 13): mp 167-169° C.; [α]_(D) ²⁰=11.1 (c=0.18, CHCl₃); IR ν_(max) 3337, 2212 cm⁻¹; ¹H NMR (CDCl₃) δ 6.59-6.55 (m, 1H), 4.08-4.05 (m, 1H), 3.53 (d, J=10.1 Hz, 1H), 3.43 (d, J=10.1 Hz, 1H), 3.28 (s, 3H), 2.37-0.89 (m), 0.91 (s, 3H); ¹³C NMR (CDCl₃) δ 147.2, 127.5, 115.9, 71.1, 66.1, 59.1, 56.2, 54.8, 48.3, 39.7, 39.3, 36.0, 34.4, 34.3, 32.8, 31.6, 29.3, 28.0, 26.9, 21.5, 16.3. Anal. Calcd for C₂₁H₃₁NO₂: C, 76.55; H, 9.48; N, 4.25. Found: C, 76.59; H, 9.32; N, 4.06.

(3α,5α,17β)-3-Hydroxy-19-methoxyandrostane-17-carbonitrile (16, MQ-92)

To a solution of steroid 15 (430 mg, 1.3 mmol) in EtOAc (30 mL) was added Pd/C (10%, 100 mg). A hydrogenation was carried out under 7 atm H₂ at room temperature for 3 h. The mixture was filtered through Celite and washed with EtOAc (100 mL). Solvents were removed and the residue was purified by flash column chromatography (silica gel eluted with 10% EtOAc in hexanes) to afford product 16 (415 mg, 96%): mp 146-148° C.; [α]_(D) ²⁰=42.1 (c=0.29, CHCl₃); ν_(max) 3412, 2235 cm⁻¹; ¹H NMR (CDCl₃) δ 4.08-4.05 (m, 1H), 3.49 (d, J=9.8 Hz, 1H), 3.39 (d, J=9.8 Hz, 1H), 3.29 (s, 3H), 2.25 (t, J=8.8 Hz, 1H), 2.10-0.79 (m), 0.92 (s, 3H); ¹³C NMR (CDCl₃) δ 121.4, 70.9, 66.3, 59.1, 54.7, 54.3, 44.5, 40.2, 39.5, 39.2, 37.5, 36.4, 36.1, 31.9, 29.4, 28.0, 27.1, 26.5, 24.5, 21.6, 14.4. Anal. Calcd for C₂₁H₃₃NO₂: C, 76.09; H, 10.03; N, 4.23. Found: C, 76.16; H, 9.90; N, 4.05.

(3α,5α)-3-Hydroxy-19-methoxypregnan-20-one (17, MQ-93)

To a solution of steroid 16 (360 mg, 1.09 mmol) in THF (20 mL) was added methyl magnesiumbromide (3.0 M, 2 mL, 6.0 mmol) at room temperature. The mixture was then refluxed for 16 h and subsequently allowed to cool to room temperature and quenched by 6 N HCl addition. The product was extracted into dichloromethane (50 mL×3). The combined organic layers were dried, filtered, and concentrated. The ¹H NMR of the crude product (300 mg, 79%) showed the 17β (steroid 17) and 17α diastereomer in the ratio of 8 to 1, respectively. The crude product was purified by flash column chromatography (silica gel eluted with 25% EtOAc in hexanes) to afford pure product 17 (135 mg) pure: mp 160-162° C.; [α]_(D) ²⁰=41.7 (c=0.31, CHCl₃); IR ν_(max) 3407, 1703 cm⁻¹; ¹H NMR (CDCl₃) δ 4.07-4.05 (m, 1H), 3.47 (d, J=9.8 Hz, 1H), 3.40 (d, J=10.2 Hz, 1H), 3.26 (s, 3H), 2.50 (t, J=9.4 Hz, 1H), 2.17-0.78 (m), 2.08 (s, 3H), 0.59 (s, 3H); ¹³C NMR (CDCl₃) δ 209.8, 70.9, 66.3, 63.8, 59.0, 56.9, 54.4, 44.3, 39.5, 39.4, 39.2, 36.1, 35.9, 31.8, 31.4, 29.3, 28.1, 26.9, 24.3, 22.6, 22.0, 13.5. Anal. Calcd for C₂₂H₃₆O₃: C, 75.82; H, 10.41. found: C, 75.71; H, 10.29.

(3α,5α)-3-(Acetyloxy)-19-methoxypregnan-20-one (18)

To a solution of steroid 17 (100 mg, 0.29 mmol) in pyridine (5 mL) was added acetic anhydride (51 mg, 0.5 mmol) and DMAP (5 mg) at room temperature. The reaction mixture was quenched by water after 2 h and extracted with EtOAc (50 mL×2). The combined organic layers were dried with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 20% EtOAc in hexanes) to give product 18 as an oil (112 mg, 100%): ¹H NMR (CDCl₃) δ 5.01-4.98 (m, 1H), 3.46 (d, J=9.8 Hz, 1H), 3.37 (d, J=9.8 Hz, 1H), 3.23 (s, 3H), 2.47 (t, J=9.0 Hz, 1H), 2.22-0.79 (m), 2.06 (s, 3H), 2.00 (s, 3H), 0.57 (s, 3H); ¹³C NMR (CDCl₃) δ 209.4, 170.5, 70.9, 69.9, 63.7, 59.0, 56.8, 54.2, 44.2, 40.1, 39.3, 39.1, 35.8, 33.1, 31.7, 31.4, 27.8, 27.7, 26.3, 24.2, 22.6, 21.9, 21.4, 13.4.

(3α,5α)-3,21-bis(Acetyloxy)-19-methoxylpregnan-20-one (19)

To a solution of steroid 18 (112 mg, 0.29 mmol) in benzene (10 mL) and methanol (0.5 mL) was added lead tetraacetate (513 mg, 1.15 mmol) and boron trifluoride ether complex (1 mL) at room temperature. After 3 h, water was added and the product extracted into EtOAc (50 mL×2). The combined organic layers were dried over with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 25% EtOAc in hexanes) to give product 19 as a foam (82 mg, 63%): ¹H NMR (CDCl₃) δ 5.03-5.01 (m, 1H), 4.70 (d, J=16.8 Hz, 1H), 4.53 (d, J=16.8 Hz, 1H), 3.47 (d, J=10.2 Hz, 1H), 3.34 (d, J=10.2 Hz, 1H), 3.25 (s, 3H), 2.47 (t, J=9.0 Hz, 1H), 2.20-0.80 (m), 2.14 (s, 3H), 2.03 (s, 3H), 0.65 (s, 3H); ¹³C NMR (CDCl₃) δ 203.8, 170.6, 170.2, 70.9, 69.9, 69.1, 59.4, 59.0, 57.1, 54.2, 45.0, 40.1, 39.2, 39.1, 35.9, 33.2, 31.8, 27.9, 27.8, 26.4, 24.4, 22.7, 22.0, 21.5, 20.4, 13.3.

(3α,5α)-3,21-Dihydroxy-19-methoxypregnan-20-one (20, MQ-98)

To a solution of steroid 19 (82 mg, 0.18 mmol) in methanol was added potassium bicarbonate (280 mg, 2.0 mmol) at room temperature. The mixture was refluxed for 5 h. Water was added and the product was extracted into EtOAc (50 mL×2). The combined organic layers were dried over with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 25% EtOAc in hexanes) to give product 20 (22 mg, 37%): mp 88-90° C.; [α]_(D) ²⁰=50.0 (c=0.13, CHCl₃); IR ν_(max) 3415, 1708 cm⁻¹; ¹H NMR (CDCl₃) δ 4.20-4.10 (m, 3H), 3.49 (d, J=9.8 Hz, 1H), 3.42 (d, J=9.8 Hz, 1H), 3.28 (d, J=1.9 Hz, 3H), 2.47 (t, J=8.6 Hz, 1H), 2.22-0.80 (m), 0.65 (J=1.2 Hz, 3H); ¹³C NMR (CDCl₃) δ 210.4, 70.9, 69.4, 66.4, 59.4, 59.1, 57.1, 54.3, 45.1, 39.5, 39.2, 39.1, 36.1, 36.0, 31.9, 29.4, 28.1, 27.0, 24.5, 22.9, 22.0, 13.6. Anal. Calcd for C₂₂H₃₆O₄: C, 72.49; H, 9.95. found: C, 72.77; H, 10.10.

19-Hydroxyandrost-5-ene-3,17-dione, 3-cyclic 1,2-ethandiyl acetal (21)

To a solution of the known 19-hydroxyandrost-4-ene-3,17-dione (1.0 g, 3.3 mmol) in benzene (100 mL) was added ethylene glycol (267 mg, 4.3 mmol) and PPTS (100 mg). The mixture was refluxed in a flask equipped with a Dean-Stark trap. After 4 h, the mixture was cooled down to room temperature and solvent was removed by reduced pressure. The residue was purified by flash column chromatography (silica gel eluted with 15% EtOAc in hexanes) to afford the known 19-hydroxyandrost-5-ene-3,17-dione, 3,17-bis(cyclic 1,2-ethandiyl acetal) (260 mg, 20%) and product 21 (450 mg, 39%): mp 190-192° C.; IR ν_(max) 3468, 1735 cm⁻¹; ¹H NMR (CDCl₃) δ 5.67-5.65 (m, 1H), 3.93-3.3.77 (m, 5H), 3.58-3.55 (m, 1H), 2.48-0.96 (m), 0.87 (s, 3H); ¹³C NMR (CDCl₃) δ 221.2, 135.4, 126.4, 109.0, 64.4, 64.2, 62.5, 52.4, 50.0, 47.8, 41.8, 41.6, 35.7, 32.8, 32.4, 31.6, 31.3, 30.0, 21.7, 20.9, 13.9.

(17β)-17,19-Dihydroxyandrost-5-en-3-one, 3-cyclic 1,2-ethandiyl acetal (22)

To a solution of steroid 21 (450 mg, 1.29 mmol) in ethanol (50 mL) was added sodium borohydride (152 mg, 4 mmol) at room temperature. After 3 h, aqueous NH₄Cl was added and the product extracted into EtOAc (50 mL×3). The combined organic layers were dried with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 35% EtOAc in hexanes) to give product 22 (374 mg, 83%): mp 208-210° C.; IR ν_(max) 3440 cm⁻¹; ¹H NMR (CDCl₃) δ 5.74-5.70 (m, 1H), 4.00-3.92 (m, 4H), 3.85 (d, J=11.4 Hz, 1H), 3.70-3.62 (m, 2H), 2.22-0.84 (m), 0.82 (s, 3H); ¹³C NMR (CDCl₃) δ 135.1, 127.3, 109.1, 81.8, 64.5, 64.3, 62.6, 52.1, 50.0, 42.9, 41.9, 41.8, 36.8, 33.4, 32.4, 31.4, 30.6, 30.5, 23.3, 21.3, 11.3.

(17β)-17,19-Dimethoxyandrost-5-en-3-one, 3-cyclic 1,2-ethandiyl acetal (23)

To a solution of steroid 22 (374 mg, 0.72 mmol) in THF (30 mL) was added sodium hydride (400 mg, 60% in mineral oil, 6.0 mmol). After addition, the mixture was refluxed for 1 h, iodomethane (2.13 g, 15 mmol) was added and reflux was continued for 3 h. After allowing cooling to room temperature, water was added and the product was extracted into EtOAc (100 mL×3). The combined organic layers were dried with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 20% EtOAc in hexanes) to give product 22 (402 mg, 100%): mp 97-99° C.; IR ν_(max) 2918, 1450, 1105 cm⁻¹; ¹H NMR (CDCl₃) δ 5.52-5.50 (m, 1H), 3.95-3.83 (m, 4H), 3.51 (d, J=9.8 Hz, 1H), 3.27 (s, 3H), 3.27 (d, J=11.4 Hz, 1H), 3.24 (s, 3H), 3.15 (t, J=7.8 Hz, 1H), 2.56-0.78 (m), 0.73 (s, 3H); ¹³C NMR (CDCl₃) δ 136.1, 124.8, 109.1, 90.6, 73.6, 64.2, 64.0, 58.8, 57.6, 51.9, 49.9, 42.6, 42.0, 40.6, 38.0, 32.6, 32.5, 31.3, 30.8, 27.5, 23.1, 21.2, 11.3.

(17β)-17,19-Dimethoxyandrost-4-en-3-one (24, MQ-99)

To a solution of steroid 23 (402 mg, 1.07 mmol) in THF (20 mL) was added 3 N HCl (10 mL at room temperature. The mixture was stirred for 2 h and the product extracted into dichloromethane (50 mL×2). The combined organic layers were dried with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 25% EtOAc in hexanes) to give product 24 (355 mg, 100%): IR ν_(max) 1671 cm⁻¹; mp 93-95° C.; [α]_(D) ²⁰=124.7 (c=0.32, CHCl₃); ¹H NMR (CDCl₃) δ 5.80 (d, J=0.7 Hz, 1H), 3.68 (d, J=9.3 Hz, 1H), 3.51 (d, J=9.4 Hz, 1H), 3.28 (s, 3H), 3.25 (s, 3H), 3.18 (t, J=8.2 Hz, 1H), 2.27-0.90 (m), 0.74 (s, 3H); ¹³C NMR (CDCl₃) δ 199.9, 167.5, 125.5, 90.2, 76.0, 59.2, 57.7, 54.1, 50.9, 42.8, 42.7, 37.8, 35.9, 34.8, 33.6, 33.4, 31.6, 27.4, 23.0, 21.2, 11.5. Anal. Calcd for C₂₁H₃₂NO₃: C, 75.86; H, 9.70. Found: C, 76.00; H, 9.98.

(3α,17β)-17,19-Dimethoxyandrost-5-en-3-ol (25, MQ-101) and (3β,17β)-17,19-Dimethoxyandrost-5-en-3-ol (26, MQ-100)

To a solution of steroid 24 (355 mg, 1.07 mmol) in acetic anhydride (10 mL) was added sodium iodide (600 mg, 4 mmol) and TMSCl (435 mg, 4 mmol) at 0° C. After addition, the mixture was allowed to warm up to room temperature for 1 h. Thin layer chromatography showed no remaining starting material. Aqueous NaHCO₃ was added and the product extracted into EtOAc (50 mL×3). The combined organic layers were dried with MgSO₄, filtered, and concentrated. The residue was dissolved in ethanol (20 mL) and NaBH₄ (200 mg) was added. After 16 h, aqueous NH₄Cl was added and the product extracted into EtOAc (50 mL×3). The combined organic layers were dried with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 30% EtOAc in hexanes) to give product 25 (30 mg, 8%), and product 26 (248 mg, 69%).

Product 25 had: mp 132-134° C.; [α]_(D) ²⁰=−64.0 (c=0.10, CHCl₃); IR ν_(max) 3337, 1446 cm⁻¹; ¹H NMR (CDCl₃) δ 5.67-5.65 (m, 1H), 4.05-4.00 (m, 1H), 3.60 (d, J=9.8 Hz, 1H), 3.35 (s, 3H), 3.31 (s, 3H), 3.28 (d, J=9.8 Hz, 1H), 3.25 (t, J=8.2 Hz, 1H), 2.64-2.60 (m, 1H), 2.17-0.85 (m), 0.80 (s, 3H); ¹³C NMR (CDCl₃) δ 134.8, 126.9, 90.8, 73.7, 66.9, 59.1, 57.9, 52.1, 50.8, 42.8, 41.5, 40.0, 38.2, 32.9, 31.1, 30.2, 29.3, 27.7, 23.3, 21.1, 11.5. Anal. Calcd for C₂₁H₃₄O₃: C, 75.41; H, 10.25. Found: C, 75.31; H, 10.41.

Product 26 had: mp 160-162° C.; [α]_(D) ²⁰=−76.7 (c=0.45, CHCl₃); IR ν_(max) 3408 cm⁻¹; ¹H NMR (CDCl₃) δ 5.53-5.50 (m, 1H), 3.54 (d, J=9.7 Hz, 1H), 3.51-3.44 (m, 1H), 3.28 (s, 3H), 3.24 (s, 3H), 3.22 (d, J=9.7 Hz, 1H), 3.18 (t, J=8.2 Hz, 1H), 2.65 (s, br, 1H), 2.32-0.76 (m), 0.73 (s, 3H); ¹³C NMR (CDCl₃) δ 136.9, 124.4, 90.7, 73.8, 71.1, 58.8, 57.7, 51.9, 50.4, 42.6, 42.2, 40.5, 38.0, 33.6, 32.6, 31.6, 30.7, 27.5, 23.1, 21.2, 11.3. Anal. Calcd for C₂₁H₃₄O₃: C, 75.41; H, 10.25. Found: C, 75.51; H, 10.30.

(3α,5α)-3-[[(Dimethylethyl)dimethylsilyl]oxy]-19-methkoxyandrostan-17on (27)

To a solution of steroid 11 (150 mg, 0.47 mmol) in DMF (5 ml) was added tert-butyldimethylsilyl chloride (150 mg, 1.0 mmol) and imidazole (132 mg, 2.0 mmol) at room temperature. After 16 h, water was added and the product extracted into EtOAc (50 mL×2). The combined organic layers were dried with MgSO₄, filtered and removed. The residue was purified by flash column chromatography (silica gel eluted with 10% EtOAc in hexanes) to afford product 27 as an oil (198 mg, 99%): ¹H NMR (CDCl₃) δ 4.00-3.95 (m, 1H), 3.51 (d, J=9.7 Hz, 1H), 3.40 (d, J=9.7 Hz, 1H), 3.27 (s, 3H), 2.44-0.80 (m), 0.89 (s, 3H), 0.87 (s, 9H), 0.00 (d, J=1.6 Hz, 6H); ¹³C NMR (CDCl₃) δ 221.6, 71.3, 66.6, 59.1, 54.7, 51.7, 47.9, 39.6, 39.2, 37.0, 35.8, 35.5, 31.8, 30.9, 29.9. 28.1, 27.2, 25.8 (3×C), 25.6, 21.7, 21.2, 13.9, −4.90, −4.92.

(3α,5α)-3-[[(Dimethylethyl)dimethylsilyl]oxy]-19-methoxyandrostan-17-one, oxime (28)

To a solution of the steroid 27 (195 mg, 0.45 mmol) in pyridine (10 mL) was added hydroxyamine hydrochloride (140 mg, 2.0 mmol) at room temperature. After 14 h, water was added and the product extracted into EtOAc (50 mL×2). The combined organic layers were dried with MgSO₄, filtered and removed. The residue was purified by flash column chromatography (silica gel eluted with 20% EtOAc in hexanes) to afford product 28 as an oil (202 mg, 100%): ¹H NMR (CDCl₃) δ 9.05 (s, br, 1H), 4.00-3.95 (m, 1H), 3.50 (d, J=9.8 Hz, 1H), 3.41 (d, J=9.8 Hz, 1H), 3.27 (s, 3H), 2.50-0.82 (m), 0.91 (s, 3H), 0.88 (s, 9H), 0.11 (d, J=1.9 Hz, 6H); ¹³C NMR (CDCl₃) δ 171.1, 71.4, 66.7, 59.1, 54.7, 54.1, 44.2, 39.6, 39.2, 37.1, 35.2, 34.3, 31.5, 30.0, 28.2, 27.1, 25.8 (3×C), 25.0, 23.1, 21.5, 18.1, 17.2, −4.85, −4.89.

(3α,5α,17β)-19-methoxy-17-nitroandrostan-3-ol (29, MQ-97)

To a solution of NBS (231 mg, 1.3 mmol) in dioxane (4 mL) was added aqueous KHCO₃ (260 mg, 2.6 mmol, 4 mL) at room temperature. The mixture was stirred for 30 min at room temperature, then the oxime (202 mg, 0.45 mmol) in dioxane (10 ml) was added. The reaction was stirred in an open flask for 14 h at room temperature. NaBH₄ was added (200 mg) in 5 portions and the reaction was stirred for 3 h at room temperature. 6 N HCl (10 ml) was slowly added and stirring at room temperature was continued for 1 h. The product was extracted into dichloromethane (50 mL×2). The combined organic layers were dried with MgSO₄, filtered, and removed. The residue was purified by flash column chromatography (silica gel eluted with 30% EtOAc in hexanes) to afford product 29 (79 mg, 50%): mp 52-54° C.; [α]_(D) ²⁰=25.8 (c=0.21, CHCl₃); IR ν_(max) 3307, 1541, 1370 cm⁻¹; ¹H NMR (CDCl₃) δ 4.38 (t, J=8.6 Hz, 1H), 4.10-4.05 (m, 1H), 3.49 (d, J=9.8 Hz, 1H), 3.41 (d, J=9.8 Hz, 1H), 3.27 (s, 3H), 2.55-0.79 (m), 0.74 (s, 3H); ¹³C NMR (CDCl₃) δ 94.5, 71.0, 66.3, 59.1, 54.2, 53.4, 46.0, 39.5, 39.1, 37.6, 36.0, 31.5, 29.3, 28.0, 27.1, 24.7, 23.6, 21.7, 12.2. Anal. Calcd for C₂₀H₃₃NO₄: C, 68.34; H, 9.46. Found: C, 68.40; H, 9.45.

(3α,5β)-3-Hydroxy-19-methoxyandrostan-17-one (30, MQ-94)

To a solution of steroid 10 (295 mg, 0.93 mmol) in THF (20 mL) was added lithium aluminum tri-tert-butoxide hydride (2.0 mmol, 1.0 M in THF, 2.0 mL) at −40° C. After 2 h, the mixture was quenched by 3 N HCl at −40° C., the reaction was allowed to warm up to room temperature for 1 h. The product was extracted into dichloromethane (100 mL×2) and washed with brine. The combined organic extracts were dried with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 30% EtOAc in hexanes) to give product 30 (239 mg, 81%): mp 208-210° C.; IR ν_(max) 3428, 1737, 1642 cm⁻¹; [α]_(D) ²⁰=81.3 (c=0.31, CHCl₃); ¹H NMR (CDCl₃) δ 3.65-3.58 (m, 1H), 3.52 (d, J=9.8 Hz, 1H), 3.43 (d, J=9.8 Hz, 1H), 3.27 (s, 3H), 2.44-0.65 (m), 0.85 (s, 3H); ¹³C NMR (CDCl₃) δ 221.4, 71.5, 70.8, 59.1, 54.6, 51.6, 47.9, 44.9, 39.0, 38.3, 35.8, 35.5, 32.0, 31.8, 31.6, 30.8, 28.0, 21.7, 21.6, 13.8. Anal. Calcd for C₂₀H₃₂O₃: C, 74.96; H, 10.06. Found: C, 75.10; H, 9.95.

(3β,5α,17β)-17,19-Dimethoxyandrostan-3-61 (31, MQ-96)

To a solution of steroid 7 (65 mg, 0.20 mmol) in THF (10 mL) was added lithium aluminum tri-tert-butoxide hydride (1.0 mmol, 1.0 M in THF, 1.0 mL) at −40° C. After 2 h, the mixture was quenched by 3 N HCl at −40° C. and the reaction was allowed to warm up to room temperature for 1 h. The product was extracted into dichloromethane (50 mL×2) and washed with brine. The combined organic layers were dried with MgSO₄, filtered, and concentrated. The residue was purified by flash column chromatography (silica gel eluted with 25% EtOAc in hexanes) to give product 31 (55 mg, 85%): mp 164-166° C.; IR ν_(max) 3370 cm⁻¹; [α]_(D) ²⁰=1.0 (c=0.10, CHCl₃); ¹H NMR (CDCl₃) δ 3.65-3.57 (m, 1H), 3.51 (d, J=10.2 Hz, 1H), 3.43 (d, J=10.2 Hz, 1H), 3.33 (s, 3H), 3.29 (s, 3H), 3.22 (t, J=8.2 Hz, 1H), 2.24-0.60 (m), 0.76 (s, 3H); ¹³C NMR (CDCl₃) δ 90.8, 71.5, 71.0, 59.1, 57.8, 54.7, 51.5, 45.0, 43.0, 38.9, 38.5, 38.4, 35.8, 32.0, 31.8, 31.6, 28.2, 27.7, 23.2, 22.2, 11.7. Anal. Calcd for C₂₁H₃₆O₃: C, 74.95; H, 10.78. Found: C, 74.91; H, 10.82.

B. [³⁵S]-TBPS Displacement

The IC₅₀ values for non-competitive displacers of [³⁵S]-TBPS from the picrotoxin binding site on GABA_(A) receptors are reported in Table 1.

TABLE 1 Inhibition of [³⁵S]-TBPS Binding by Example Compounds^(a) Compound IC₅₀ (nM) n_(Hill) 7, MQ-88 (Prodrug)  8,700 ± 1,500 1.27 ± 0.15 8, MQ-89 56 ± 2 1.05 ± 0.03 10 (Prodrug) — — 11, KK-125  4,300 ± 1,200 0.95 ± 0.15 12, MQ-90 79 ± 4 1.06 ± 0.04 15, MQ-91 118 ± 13 1.01 ± 0.10 16, MQ-92 63 ± 7 1.24 ± 0.14 17, MQ-93 47 ± 4 1.17 ± 0.09 20, MQ-98 345 ± 61 0.88 ± 0.12 24, MQ-99 (Prodrug)  14,500 ± 10,700 1.24 ± 0.47 25, MQ-101 583 ± 71 0.94 ± 0.09 26, MQ-100 (Prodrug) 17,800 ± 8,400 1.19 ± 0.24 29, MQ-97 37 ± 4 0.88 ± 0.08 30, MQ-94 (Prodrug) >30,000 — 31, MQ-96 (Prodrug)  7,800 ± 2,900 1.27 ± 0.33 ^(a)Results presented are from duplicate experiments performed in triplicate. Error limits are calculated as standard error of the mean. Methods used are known in the art (see Jiang, X., et al., Neurosteroid analogues. 9. Conformationally constrained pregnanes: structure-activity studies of 13,24-cyclo-18,21-dinorcholane analogues of the GABA modulatory and anesthetic steroids (3α,5α)- and (3α,5α)-3-hydroxypregnan-20-one. J. Med. Chem., 46: 5334-48 (2003) - the contents of which are hereby incorporated by reference in their entirety). C. Electrophysiology Results

The compounds of the present disclosure were evaluated for the ability to potentiate chloride currents mediated by 2 μM GABA at rat α₁β₂γ_(2L) type GABA_(A) receptors expressed in Xenopus laevis oocytes and the results are shown in Table 2.

TABLE 2 Modulation of Rat α₁β₂γ_(2L) GABA_(A) Receptor Function by Example Compounds oocyte electrophysiology^(a) Compound 0.1 μM 1 μM 10 μM (gating) 10 μM 7, MQ-88 1.00 ± 0   0.85 ± 0.01 1.07 ± 0.02 0.04 ± 0.03 (Prodrug) 8, MQ-89 1.65 ± 0.08 7.63 ± 0.77 20.9 ± 2.73 0.22 ± 0.01 10 (Prodrug) — — — — 11, KK-125 0.71 ± 0.02 0.76 ± 0.07 2.17 ± 0.12   0 ± 0.07 12, MQ-90 1.24 ± 0.05 7.40 ± 1.43 18.7 ± 6.19 0.14 ± 0.04 15, MQ-91 1.27 ± 0.13 5.34 ± 0.86 25.6 ± 3.23 0.10 ± 0.09 16, MQ-92 1.52 ± 0.02 9.79 ± 0.53 25.7 ± 2.11 0.25 ± 0.11 17, MQ-93 2.15 ± 0.19 12.8 ± 1.74 33.8 ± 5.44 0.23 ± 0.07 20, MQ-98 0.98 ± 0.01 2.76 ± 0.27 19.0 ± 2.31 0.09 ± 0.05 24, MQ-99 0.88 ± 0.08 0.63 ± 0.06 1.06 ± 0.17 0.11 ± 0.17 (Prodrug) 25, MQ-101 0.94 ± 0.07 1.97 ± 0.08 15.7 ± 0.90 0.08 ± 0.07 26, MQ-100 0.83 ± 0.03 0.76 ± 0.02 0.78 ± 0.02 0.02 ± 0.02 (Prodrug) 29, MQ-97 2.07 ± 0.09 15.7 ± 1.45 26.6 ± 4.34 0.11 ± 0.01 30, MQ-94 0.90 ± 0.02 0.88 ± 0.01 0.84 ± 0.02 0.03 0.02 (Prodrug) 31, MQ-96 0.91 ± 0.02 0.97 ± 0.05 1.10 ± 0.05 0.02 ± 0   (Prodrug) ^(a)The GABA concentration used for the control response was 2 μM. Each compound was evaluated on at least four different oocytes at the concentrations indicated, and the results reported are the ratio of currents measured in the presence/absence of added compound. Gating represents direct current gated by 10 μM compound in the absence of GABA, and this current is reported as the ratio of compound only current/2 μM GABA current. Error limits are calculated as standard error of the mean (N ≧ 4). Methods used are known in the art (see Jiang, X., et al.). D. Tadpole Loss of Righting and Swimming

Table 3 discloses the anesthetic effects of the compounds of the present disclosure. In particular, the anesthetic effect of the compounds of the present disclosure on Loss of Righting Reflex (LRR) and Loss of Swimming Reflex (LSR).

TABLE 3 Effects of Examples on Tadpole Righting and Swimming Reflexes^(a) Tadpole LRR Tadpole Tadpole Tadpole EC₅₀ LRR LSR LSR Compound (μM) n_(Hill) EC₅₀ (μM) n_(Hill) 7, MQ-88 1.71 ± 0.25 −2.41 ± 0.56 5.48 ± 0.12  −33.3 ± 0.10 (Prodrug) 8, MQ-89 332 ± 43  −2.32 ± 0.75 1.07 ± 0.01  −16.1 ± 0.64 10 (Prodrug) — — — — 11, KK-125 7.95 ± 3.29 −1.81 ± 0.97 17.3 ± 0.2  −36.2 ± 0.2 12, MQ-90 1.73 ± 0.05 −2.53 ± 0.11 3.54 ± 2.33 −17.9 ± 71  15, MQ-91 1.22 ± 0.94 −7.11 ± 28.0 2.71 ± 0   −21.4 ± 0.7 16, MQ-92 0.36 ± 0.04 −3.37 ± 1.34 0.99 ± 0.17 −21.7 ± 0.6 17, MQ-93 0.36 ± 0.04 −2.74 ± 1.12 1.71 ± 0.03 −36.3 ± 0.1 20, MQ-98 3.15 ± 0.50 −2.54 ± 1.23 5.48 ± 0.12 −33.3 ± 0.1 24, MQ-99 None — None — (Prodrug) 25, MQ-101 3.38 ± 0.38 −2.80 ± 1.13 10.5 ± 0   −21.1 ± 0  26, MQ-100 None — None — (Prodrug) 29, MQ-97 0.16 ± 0.01 −1.84 ± 0.11 0.55 ± 0.01 −33.3 ± 0.1 30, MQ-94 >10 — None — (Prodrug) 31, MQ-96 7.04 ± 1.98 −1.66 ± 0.51 16.8 ± 5.9  −3.27 ± 2.5 (Prodrug)

Methods used are known in the art (see Jiang, X., et al.). Error limits are calculated as standard error of the mean (N=10 or more animals at each of five or more different concentrations).

General Methods

The compounds discussed in the present disclosure were produced as discussed elsewhere throughout this disclosure and by the following methods.

Solvents were either used as purchased or dried and purified by standard methodology. Extraction solvents were dried with anhydrous Na₂SO₄ and after filtration, removed on a rotary evaporator. Flash chromatography was performed using silica gel (32-63 μm) purchased from Scientific Adsorbents (Atlanta, Ga.). Melting points were determined on a Kofler micro hot stage and are uncorrected. FT-IR spectra were recorded as films on a NaCl plate. NMR spectra were recorded in CDCl₃ at ambient temperature at 300 MHz (¹H) or 74 MHz (¹³C). Purity was determined by TLC on 250 μm thick Uniplates™ from Analtech (Newark, Del.). All pure compounds (purity >95%) gave a single spot on TLC. Elemental analyses were performed by M-H-W Laboratories (Phoenix, Ariz.).

Equivalents and Scope

In view of the above, it will be seen that the several advantages of the disclosure are achieved and other advantageous results attained. As various changes could be made in the above processes and composites without departing from the scope of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

When introducing elements of the present disclosure or the various versions, embodiment(s) or aspects thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. It is also noted that the terms “comprising”, “including”, “having” or “containing” are intended to be open and permits the inclusion of additional elements or steps. 

What is claimed is:
 1. A compound of Formula (I-g):

or a pharmaceutically acceptable salt thereof; wherein: R₁ is selected from (C₁-C₄ alkyl)-O, spirooxirane, cyano, ═O, nitro, (C₁-C₄ alkyl)C(O), and HO(C₁-C₄ alkyl)C(O); R₂ is ═O, H, or OR_(a), where R_(a) is selected from H, optionally substituted C₁-C₄ alkyl, or optionally substituted aryl, with the proviso that when R₂ is ═O, R₈ is not present; R₃ is H, optionally substituted C₁-C₄ alkyl, optionally substituted C₂-C₄ alkenyl, optionally substituted C₂-C₄ alkynyl, or optionally substituted aryl; R_(b) is methyl; R₈, when present, is H or optionally substituted C₁-C₄ alkyl; - - - denotes an optional, additional C—C bond, resulting in a C═C bond between C₁₆-C₁₇, with the proviso that when present, the R₁ is not ═O or spirooxirane.
 2. The compound of claim 1, wherein the R₃ group is selected from the group consisting of H, methyl, and trifluoromethyl.
 3. The compound of claim 1, wherein R₂ is ═O, methoxy or H.
 4. The compound of claim 1, wherein R₁ is beta-cyano.
 5. The compound of claim 1 selected from the group consisting of:

and pharmaceutically acceptable salts thereof.
 6. The compound of claim 1, wherein R₁ is selected from (C₁-C₄ alkyl)-O, spirooxirane, cyano, ═O, (C₁-C₄ alkyl)C(O), and HO(C₁-C₄ alkyl)C(O).
 7. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 8. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 9. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 10. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 11. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 12. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 13. A pharmaceutical composition comprising a compound of formula:

or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.
 14. A pharmaceutical composition comprising a compound of formula:

or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.
 15. A pharmaceutical composition comprising a compound of formula:

or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.
 16. A pharmaceutical composition comprising a compound of formula:

or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.
 17. A pharmaceutical composition comprising a compound of formula:

or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.
 18. A pharmaceutical composition comprising a compound of formula:

or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient. 